Apparatuses, systems and methods for imaging micro-objects

ABSTRACT

The present disclosure relates to an optical apparatus for imaging and/or manipulating micro-objects in a microfluidic device, such as a light-actuated microfluidic (LAMF) device, and related systems and methods. The optical apparatus can comprise a structured light modulator, a first and a second tube lens, an objective lens, a dichroic beam splitter, and an image sensor. The structured light modulator can be configured to receive unstructured light beams and transmit structured light beams for illuminating micro-objects located within an enclosure of the microfluidic device and/or selectively activating one or more of a plurality of dielectrophoresis (DEP) electrodes of the microfluidic device. The first tube lens can be configured to capture the structured light beams transmitted by the structured light modulator. The second tube lens can be configured to transmit image light beams from the dichroic beam splitter to the image sensor. The image sensor can be configured to receive image light beams from the second tube lens. The image light beams received by the image sensor can be used to form an image of at least a portion of the microfluidic device.

PRIORITY CLAIM AND INCORPORATION BY REFERENCE

This application is continuation of International Patent Application No.PCT/US2017/064308, filed Dec. 1, 2017, claiming the benefit under 35U.S.C. 119(e) of U.S. Provisional Application No. 62/429,066, filed onDec. 1, 2016, each of which is herein incorporated by reference in itsentirety.

All publications and patent applications mentioned in this specificationare incorporated herein by reference in their entirety to the sameextent as if each individual publication or patent application wasspecifically and individually indicated to be incorporated by reference.

BACKGROUND

As the field of microfluidics continues to progress, microfluidicdevices have become convenient platforms for processing and manipulatingmicro-objects such as biological cells. For example, light-actuatedmicrofluidic devices offer some desirable capabilities, including theability to select and manipulate individual micro-objects. In general,light-actuated microfluidic devices (e.g., optoelectronic tweezers (OET)devices) utilize optically induced dielectrophoresis (DEP) to manipulatemicro-objects. For example, micro-objects can be moved around and mergedwithin the microfluidic devices. Simultaneous manipulation, analysis andselection of micro-objects such as single cells can be valuable inbiologic discovery and development as well as single cell annotation andgenomics.

However, conventional microscopes are not designed to view themicro-objects in microfluidic devices, particularly light actuatedmicrofluidic devices. Thus, the images of the micro-objects obtained byusing conventional microscopes may have large aberrations, which degradethe quality of the images. In addition, the optical apparatus design ina conventional microscope may have some amount of out-of-focus light inthe images, which may result in high level of noise in the images anddecrease the contrast and resolution of the images. Furthermore, thereis often mechanical constraint for the optical apparatus because of thelimited compact space available for the optical apparatus for themicro-fluidic devices. Therefore, there is a need to developapparatuses, systems and related methods for imaging and manipulatingmicro-objects to overcome the problems and challenges discussed above.

SUMMARY OF THE DISCLOSURE

The present disclosure relates to optical apparatuses, systems andmethods for imaging and manipulating micro-objects. In particular, thedisclosure relates to an optical apparatus for imaging and manipulatingmicro-objects in a light-actuated microfluidic device and relatedsystems and methods.

Disclosed herein is an optical apparatus for imaging and/or manipulatingmicro-objects in a microfluidic device, such as a light-actuatedmicrofluidic (LAMF) device. The optical apparatus can comprise a firstlight source, a structured light modulator, a first tube lens, anobjective lens, a dichroic beam splitter, a second tube lens and animage sensor. The structured light modulator can be configured toreceive unstructured light beams from the first light source andtransmit structured light beams to the first tube lens. The structuredlight beams can be suitable for selectively activating one or more of aplurality of dielectrophoresis (DEP) electrodes on a surface of asubstrate of a LAMF device. The first tube lens can be configured tocapture the structured light beams from the structured light modulator.The objective lens can be configured to image at least a portion of anenclosure of a microfluidic device within a field of view. The enclosurecan include a flow region and/or a plurality of sequestration pens, eachsequestration pen of the plurality is fluidically connected to the flowregion. The dichroic beam splitter can be configured to reflect (ortransmit) structured light beams from the first tube lens to theobjective lens and to transmit (or reflect) image light beams receivedfrom the objective lens to the second tube lens. The second tube lenscan be configured to receive the image light beams from the dichroicbeam splitter and to transmit the light beams to an image sensor. Theimage sensor can be configured to receive the image light beams from thesecond tube lens and generate an image of the at least a portion of theenclosure of the microfluidic device therefrom. The optical apparatuscan be configured to perform imaging, analysis and manipulation of oneor more micro-objects within the enclosure of the microfluidic device.

In some embodiments, the first tube lens has a clear aperture largerthan 45 mm and is configured to capture all light beams from thestructured light modulator. In some embodiments, the structured lightmodulator comprises an active area of at least 15 mm (e.g., at least15.5 mm, 16.0 mm, 16.5 mm, 17.0 mm, or greater). In some embodiments,the first tube lens has an effective focal length of about 162 mm orshorter (e.g., about 161 mm, about 160 mm, about 159 mm, about 158 mm,about 157 mm, about 156 mm, about 155 mm, or shorter). In someembodiments, the first tube lens has an effective focal length of about155 mm.

In some embodiments, the optical apparatus can further comprise a secondlight source configured to provide unstructured bright fieldillumination. In some embodiments, the optical apparatus can furthercomprise a third light source. The second (or third) light source canbe, for example, an LED or a laser light source. The laser light sourcecan be configured to heat up a surface within the enclosure of themicrofluidic device and/or fluidic medium located within the enclosure.Heating of the surface or medium can result in the production of gas(e.g., a bubble).

In some embodiments, the optical apparatus can further comprise a nestconfigured to secure the microfluidic device during imaging. The nestcan be further configured to provide at least one electrical connectionto the microfluidic device and/or fluidic connections.

In some embodiments, the structured light modulator transmits aplurality of illumination light beams. In some embodiments, the opticalapparatus is configured to illuminate a plurality of sequestration penswith a plurality of illumination spots. For example, each sequestrationpen of the plurality can be illuminated with a single illumination spot,and each illumination spot can be sized to illuminate all or a portionof the sequestration pen which it is illuminating. In some embodiments,each of the plurality of illumination spots has a size of about 60microns×120 microns. In some embodiments, each of the plurality ofillumination spots has an area of about 7000 to about 20000 squaremicrons (e.g., about 7000 square microns to about 10,000 square microns,about 10,000 square microns to about 15,000 square microns, about 15,000square microns to about 20,000 square microns, of any range defined bytwo of the foregoing endpoints).

In some embodiments, the optical apparatus is further configured suchthat the portion of the enclosure within the field of view issimultaneously in focus at the image sensor and at the structure lightmodulator. In some embodiments, the optical apparatus is furtherconfigured such that only a portion of the enclosure (e.g., an interiorarea of the flow region and/or each of the plurality of sequestrationpens) is imaged onto the image sensor in order to reduce overall noiseto achieve high image quality. In some embodiments, the structured lightmodulator is disposed at a conjugate plane of the image sensor. In someembodiments, the optical apparatus is further configured to performconfocal imaging. In other embodiments, the optical apparatus includes aslide lens which is slideably positioned between the structured lightmodulator and the first tube lens, wherein the slide lens is configuredto support ptychographic microscopy.

In some embodiments, the objective lens is configured to minimizeaberration in the image of at least the portion of the plurality ofsequestration pens. In some embodiments, the second tube lens isconfigured to correct a residual aberration of the objective lens. Insome embodiments, the optical apparatus can further comprise acorrection lens configured to correct a residual aberration of theobjective lens. The corrective lens can be located in front of theobjective lens (i.e., between the objective lens and the microfluidicdevice) or behind the objective lens (i.e., between the objective lensand the dichroic beam splitter).

In some embodiments, the optical apparatus can further comprise acontrol unit configured to adjust an illumination pattern of thestructured light modulator to selectively activate the one or more ofthe plurality of DEP electrodes and generate DEP forces to move the oneor more micro-objects inside the plurality of sequestration pens. Insome embodiments, the optical apparatus can further comprise a controlunit configured to adjust an illumination pattern of the structuredlight modulator to illuminate select regions within the microfluidicapparatus (e.g., a portion of the flow region and/or a portion of one ormore sequestration pens) and, optionally, one or more micro-objectslocated within the select regions.

Disclosed herein is a system for imaging and manipulating micro-objects.The system can comprise a microfluidic device, such as a light-actuatedmicrofluidic (LAMF) device, an optical apparatus, and a nest. Themicrofluidic device can comprise an enclosure and a substrate comprisinga surface and a plurality of dielectrophoresis (DEP) electrodes on thesurface. In some embodiments, the enclosure of the microfluidic devicecomprises a flow region and, optionally, a plurality of sequestrationpens, each sequestration pen of the plurality fluidically connected tothe flow region. The flow region and the plurality of sequestration pensmay be disposed on the substrate surface. The optical apparatus, whichmay be any of the optical apparatus described herein, can be configuredto perform imaging, analysis, and/or manipulation of one or moremicro-objects within the enclosure.

In some embodiments, the system further comprises a control unitconfigured to adjust an illumination pattern of the structured lightmodulator to selectively activate one or more of the plurality of DEPelectrodes of the substrate of the microfluidic device, therebygenerating DEP forces sufficient to move the one or more cells insidethe enclosure. In some embodiments, the system further comprises acontrol unit configured to adjust an illumination pattern of thestructured light modulator to illuminate select regions within themicrofluidic apparatus (e.g., a portion of the flow region and/or aportion of one or more sequestration pens) and, optionally, one or moremicro-objects located within the select regions.

In some embodiments, the system is configured to illuminate at least aportion of the enclosure, including any portion of a flow region and/ora plurality of sequestration pens located within the field of view, witha plurality of illumination spots. For example, each sequestration penin the field of view can be illuminated with one or more illuminationspots, and each illumination spot can be sized to illuminate all or aportion of the sequestration pen which it is illuminating. In someembodiments, each of the plurality of illumination spots has a size ofabout 60 microns×120 microns. In some embodiments, each of the pluralityof illumination spots has an area of about 7000 to about 20000 squaremicrons (e.g., about 7000 square microns to about 10,000 square microns,about 10,000 square microns to about 15,000 square microns, about 15,000square microns to about 20,000 square microns, of any range defined bytwo of the foregoing endpoints).

Disclosed herein is a method of manipulating one or more micro-objectsof a sample. The method can comprise a step of loading the samplecontaining the one or more micro-objects into a microfluidic device,such as a light-actuated microfluidic (LAMF) device. The microfluidicdevice can have an enclosure comprising a substrate having a surface anda plurality of dielectrophoresis (DEP) electrodes on the surface. Themicrofluidic device can further comprise a flow region and, optionally,a plurality of sequestration pens, each sequestration pen of theplurality fluidically connected to the flow region. The method cancomprise a step of applying a voltage potential across the microfluidicdevice.

The method can further comprise a step of selectively activating a DEPforce adjacent to at least one micro-object located within themicrofluidic device by using an optical apparatus to project structuredlight onto a first position on the surface of the substrate of themicrofluidic device, wherein the first position is located adjacent to asecond position on the surface of the substrate, the second positionlocated beneath the at least one micro-object. The optical apparatus canbe any optical apparatus described herein.

The method can further comprise a step of shifting the location of theDEP force generated adjacent to at least one micro-object by using theoptical apparatus to move the structured light from the first positionon the surface of the substrate of the microfluidic device to a thirdposition on the surface of the substrate.

In some embodiments, the method can further comprise a step of capturingthe image of at least a portion of the enclosure of the microfluidicdevice with the image sensor. In some embodiments, the imaged portion ofthe enclosure of the microfluidic device comprises a flow region and/orat least one sequestration pen, and at least one micro-object.

In some embodiments, the structured light projected onto the firstposition on the substrate surface comprises a plurality of illuminationspots. In some embodiments, the first position on the substrate surfaceis located in the flow region of the microfluidic device, and the thirdposition on the substrate surface is located within one of thesequestration pens of the plurality of sequestration pens. In someembodiments, the structured light projected onto the first position onthe substrate surface comprises a shape like a line segment or a caretsymbol. In some embodiments, the structured light projected onto thefirst position on the substrate surface has a shape like the outline ofa polygon (e.g., a square, rectangle, rhombus, pentagon, etc.), acircle, or the like.

In some embodiments, the method can further comprise a step ofselectively activating DEP forces adjacent to a plurality ofmicro-objects located within the microfluidic device by using theoptical apparatus to project structured light onto a plurality of firstpositions on the surface of the substrate of the microfluidic device,wherein each of the plurality of first positions is located adjacent toa corresponding second position on the surface of the substrate, thecorresponding second positions located beneath correspondingmicro-objects of the plurality.

In some embodiments, the method can further comprise a step of shiftingthe location of the DEP forces generated adjacent to the plurality ofmicro-objects by using the optical apparatus to move the imagedstructured light from the plurality of first positions on the substratesurface to a plurality of corresponding third positions on the substratesurface.

In some embodiments, the method can further comprise a step of capturingan image of at least a portion of the enclosure comprises imaging onlyan interior area of the flow region and/or each sequestration penlocated in the portion of the enclosure being imaged, thereby reducingoverall noise to achieve high image quality. In some embodiments, themethod can further comprise a step of analyzing the image to providefeedback and adjustment of the first position.

Disclosed herein is a method of imaging one or more micro-objects of asample. The method can comprise loading the sample containing the one ormore micro-objects into a microfluidic apparatus having an enclosurecomprising a flow region, capturing a plurality of images of at least aportion of the enclosure containing the one or more micro-objects usinga plurality of corresponding illumination patterns projected into the atleast a portion of the enclosure, and combining the plurality of imagesto generate a single image of the one or more micro-objects located inthe portion of the enclosure. In certain embodiments, each illuminationpattern of the plurality is produced using structured light and isdifferent from the other illumination patterns of the plurality. Incertain embodiments, the plurality of images is captured using anoptical system, which can be any of the optical systems disclosedherein. In certain embodiments, combining the plurality of imagescomprises processing each of the plurality of images to removeout-of-focus background light.

In some embodiments, an illumination pattern projected into the at leasta portion of the enclosure and the corresponding image captured at theimage sensor are simultaneously in focus. In some embodiments, theplurality of corresponding illumination patterns is configured to scanthrough the field of view (e.g., the entire field of view) within theenclosure.

Disclosed herein is a tube lens of an optical apparatus for amicrofluidic device, such as a light-actuated microfluidic (LAMF)device. The tube lens can comprise a first surface having a convex shapeand a first positive radius of curvature, a second surface having asecond radius of curvature, a third surface having a concave shape and athird negative radius of curvature, a fourth surface having a concaveshape and a fourth negative radius of curvature, and a clear aperturewith a diameter lager than 45 mm, wherein a front focal point and a backfocal point of the tube lens are not equally spaced from a midpoint andare not located symmetric.

In some embodiments, a Back Focal Length (BFL) is minimized. In someembodiments, the tube lens has an Effective Focal Length (EFL) of about155 mm and a Back Focal Length (BFL) of about 135 mm. In someembodiments, the tube lens has an Effective Focal Length (EFL) of about162 mm and a Back Focal Length (BFL) of about 146 mm. In someembodiments, the tube lens has an Effective Focal Length (EFL) of about180 mm and a Back Focal Length (BFL) of about 164 mm.

In some embodiments, the tube lens has an Effective Focal Length (EFL)of about 155 mm, wherein the first positive radius of curvature is about91 mm, the second radius of curvature is about 42 mm, the third negativeradius of curvature is about −62 mm, and the fourth negative radius ofcurvature is about −116 mm.

In some embodiments, the tube lens has an Effective Focal Length (EFL)of about 162 mm, wherein the first positive radius of curvature is about95 mm, the second radius of curvature is about 54 mm, the third negativeradius of curvature is about −56 mm, and the fourth negative radius ofcurvature is about −105 mm.

In some embodiments, the tube lens has an Effective Focal Length (EFL)of about 180 mm, wherein the first positive radius of curvature is about95 mm, the second radius of curvature is about 64 mm, the third negativeradius of curvature is about −60 mm, and the fourth negative radius ofcurvature is about −126 mm.

In some embodiments, the tube lens has an Effective Focal Length (EFL)of about 200 mm, wherein the first positive radius of curvature is about160 mm, the second radius of curvature is about −62 mm, the thirdnegative radius of curvature is about −80 mm, and the fourth negativeradius of curvature is about −109 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe claims that follow. A better understanding of the features andadvantages of the disclosure will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the disclosure are utilized, and theaccompanying drawings of which:

FIG. 1A illustrates an example of a microfluidic device and a system foruse with the microfluidic device, including associated control equipmentaccording to some embodiments of the disclosure.

FIGS. 1B and 1C illustrate vertical and horizontal cross-sectionalviews, respectively, of a microfluidic device according to someembodiments of the disclosure.

FIGS. 2A and 2B illustrate vertical and horizontal cross-sectionalviews, respectively, of a microfluidic device having isolation pensaccording to some embodiments of the disclosure.

FIG. 2C illustrates a detailed horizontal cross-sectional view of asequestration pen according to some embodiments of the disclosure.

FIG. 2D illustrates a partial horizontal cross-sectional view of amicrofluidic device having isolation pens according to some embodimentsof the disclosure.

FIGS. 2E and 2F illustrate detailed horizontal cross-sectional views ofsequestration pens according to some embodiments of the disclosure.

FIG. 2G illustrates a microfluidic device having isolation pensaccording to some embodiments of the disclosure.

FIG. 2H illustrates a microfluidic device according to some embodimentsof the disclosure.

FIG. 3A illustrates a system which can be used to operate and observe amicrofluidic device according to some embodiments of the disclosure.

FIG. 3B illustrates an optical apparatus for a microfluidic deviceaccording to some embodiments of the disclosure.

FIG. 4A is a schematic of a system including an optical apparatus and amicrofluidic device according to some embodiments of the disclosure.

FIG. 4B illustrates an example of a plurality of sequestration pens inthe microfluidic device of FIG. 4A.

FIG. 4C illustrates a first tube lens of the optical apparatus isconfigured to capture all light beams from a structured light modulatorin FIG. 4A.

FIG. 5A is a schematic of a plurality of light sources for an opticalapparatus and a microfluidic device according to some other embodimentsof the disclosure.

FIG. 5B illustrates an example dichromic beam splitter for the pluralityof light sources for the optical apparatus in FIG. 5A.

FIG. 5C is a schematic of another embodiment of a system including anoptical apparatus and a microfluidic device.

FIG. 6A is a schematic of a system including an optical apparatus withan excitation filter and an emission filter according to some otherembodiments of the disclosure.

FIG. 6B is a schematic of a system including an optical apparatus wherea beam splitter is configured to reflect light beams from a first lightsource according to some other embodiments of the disclosure.

FIG. 6C is a schematic of a system including an optical apparatus with acorrection lens to compensate aberration according to yet some otherembodiments of the disclosure.

FIG. 7A is an optical schematic of an example tube lens of an opticalapparatus for a microfluidic device.

FIG. 7B is an optical schematic of another example tube lens of anoptical apparatus for a microfluidic device.

FIG. 7C is an optical schematic of yet another example tube lens of anoptical apparatus for a microfluidic device.

FIG. 7D is an optical schematic of another example tube lens of anoptical apparatus for a microfluidic device.

FIGS. 8A-8D illustrate various embodiments of optical configurationsthat can be used by the optical system.

FIG. 9A illustrates a schematic of a simplified portion of the opticaltrain according to some embodiments.

FIG. 9B illustrates a schematic of a simplified portion of the opticaltrain that has been modified to include a slide lens for ptychographicmicroscopy according to some embodiments.

DETAILED DESCRIPTION

This specification describes exemplary embodiments and applications ofthe invention. The invention, however, is not limited to these exemplaryembodiments and applications or to the manner in which the exemplaryembodiments and applications operate or are described herein. Moreover,the figures may show simplified or partial views, and the dimensions ofelements in the figures may be exaggerated or otherwise not inproportion. In addition, as the terms “on,” “attached to,” “connectedto,” “coupled to,” or similar words are used herein, one element (e.g.,a material, a layer, a substrate, etc.) can be “on,” “attached to,”“connected to,” or “coupled to” another element regardless of whetherthe one element is directly on, attached to, connected to, or coupled tothe other element or there are one or more intervening elements betweenthe one element and the other element. Also, unless the context dictatesotherwise, directions (e.g., above, below, top, bottom, side, up, down,under, over, upper, lower, horizontal, vertical, “x,” “y,” “z,” etc.),if provided, are relative and provided solely by way of example and forease of illustration and discussion and not by way of limitation. Inaddition, where reference is made to a list of elements (e.g., elementsa, b, c), such reference is intended to include any one of the listedelements by itself, any combination of less than all of the listedelements, and/or a combination of all of the listed elements. Sectiondivisions in the specification are for ease of review only and do notlimit any combination of elements discussed.

As used herein, “substantially” means sufficient to work for theintended purpose. The term “substantially” thus allows for minor,insignificant variations from an absolute or perfect state, dimension,measurement, result, or the like such as would be expected by a personof ordinary skill in the field but that do not appreciably affectoverall performance. When used with respect to numerical values orparameters or characteristics that can be expressed as numerical values,“substantially” means within ten percent.

The term “ones” means more than one.

As used herein, the term “plurality” can be 2, 3, 4, 5, 6, 7, 8, 9, 10,or more.

As used herein, the term “disposed” encompasses within its meaning“located.”

As used herein, a “microfluidic device” or “microfluidic apparatus” is adevice that includes one or more discrete microfluidic circuitsconfigured to hold a fluid, each microfluidic circuit comprised offluidically interconnected circuit elements, including but not limitedto region(s), flow path(s), channel(s), chamber(s), and/or pen(s), andat least one port configured to allow the fluid (and, optionally,micro-objects suspended in the fluid) to flow into and/or out of themicrofluidic device. Typically, a microfluidic circuit of a microfluidicdevice will include a flow region, which may include a microfluidicchannel, and at least one chamber, and will hold a volume of fluid ofless than about 1 mL, e.g., less than about 750, 500, 250, 200, 150,100, 75, 50, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, or 2 μL. In certainembodiments, the microfluidic circuit holds about 1-2, 1-3, 1-4, 1-5,2-5, 2-8, 2-10, 2-12, 2-15, 2-20, 5-20, 5-30, 5-40, 5-50, 10-50, 10-75,10-100, 20-100, 20-150, 20-200, 50-200, 50-250, or 50-300 μL. Themicrofluidic circuit may be configured to have a first end fluidicallyconnected with a first port (e.g., an inlet) in the microfluidic deviceand a second end fluidically connected with a second port (e.g., anoutlet) in the microfluidic device.

As used herein, a “nanofluidic device” or “nanofluidic apparatus” is atype of microfluidic device having a microfluidic circuit that containsat least one circuit element configured to hold a volume of fluid ofless than about 1 μL, e.g., less than about 750, 500, 250, 200, 150,100, 75, 50, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 nL or less. Ananofluidic device may comprise a plurality of circuit elements (e.g.,at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 50, 75, 100, 150, 200,250, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500, 3000,3500, 4000, 4500, 5000, 6000, 7000, 8000, 9000, 10,000, or more). Incertain embodiments, one or more (e.g., all) of the at least one circuitelements is configured to hold a volume of fluid of about 100 pL to 1nL, 100 pL to 2 nL, 100 pL to 5 nL, 250 pL to 2 nL, 250 pL to 5 nL, 250pL to 10 nL, 500 pL to 5 nL, 500 pL to 10 nL, 500 pL to 15 nL, 750 pL to10 nL, 750 pL to 15 nL, 750 pL to 20 nL, 1 to 10 nL, 1 to 15 nL, 1 to 20nL, 1 to 25 nL, or 1 to 50 nL. In other embodiments, one or more (e.g.,all) of the at least one circuit elements is configured to hold a volumeof fluid of about 20 nL to 200 nL, 100 to 200 nL, 100 to 300 nL, 100 to400 nL, 100 to 500 nL, 200 to 300 nL, 200 to 400 nL, 200 to 500 nL, 200to 600 nL, 200 to 700 nL, 250 to 400 nL, 250 to 500 nL, 250 to 600 nL,or 250 to 750 nL.

A “microfluidic channel” or “flow channel” as used herein refers to aflow region of a microfluidic device having a length that issignificantly longer than both the horizontal and vertical dimensions.For example, the flow channel can be at least 5 times the length ofeither the horizontal or vertical dimension, e.g., at least 10 times thelength, at least 25 times the length, at least 100 times the length, atleast 200 times the length, at least 500 times the length, at least1,000 times the length, at least 5,000 times the length, or longer. Insome embodiments, the length of a flow channel is in the range of fromabout 50,000 microns to about 500,000 microns, including any rangetherebetween. In some embodiments, the horizontal dimension is in therange of from about 100 microns to about 1000 microns (e.g., about 150to about 500 microns) and the vertical dimension is in the range of fromabout 25 microns to about 200 microns, e.g., from about 40 to about 150microns. It is noted that a flow channel may have a variety of differentspatial configurations in a microfluidic device, and thus is notrestricted to a perfectly linear element. For example, a flow channelmay include one or more sections having any of the followingconfigurations: curve, bend, spiral, incline, decline, fork (e.g.,multiple different flow paths), and any combination thereof. Inaddition, a flow channel may have different cross-sectional areas alongits path, widening and constricting to provide a desired fluid flowtherein.

As used herein, the term “obstruction” refers generally to a bump orsimilar type of structure that is sufficiently large so as to partially(but not completely) impede movement of target micro-objects between twodifferent regions or circuit elements in a microfluidic device. The twodifferent regions/circuit elements can be, for example, a microfluidicsequestration pen and a microfluidic channel, or a connection region andan isolation region of a microfluidic sequestration pen.

As used herein, the term “constriction” refers generally to a narrowingof a width of a circuit element (or an interface between two circuitelements) in a microfluidic device. The constriction can be located, forexample, at the interface between a microfluidic sequestration pen and amicrofluidic channel, or at the interface between an isolation regionand a connection region of a microfluidic sequestration pen.

As used herein, the term “transparent” refers to a material which allowsvisible light to pass through without substantially altering the lightas is passes through.

As used herein, the term “micro-object” refers generally to anymicroscopic object that may be isolated and/or manipulated in accordancewith the present invention. Non-limiting examples of micro-objectsinclude: inanimate micro-objects such as microparticles; microbeads(e.g., polystyrene beads, Luminex™ beads, or the like); magnetic beads;microrods; microwires; quantum dots, and the like; biologicalmicro-objects such as cells; biological organelles; vesicles, orcomplexes; synthetic vesicles; liposomes (e.g., synthetic or derivedfrom membrane preparations); lipid nanorafts, and the like; or acombination of inanimate micro-objects and biological micro-objects(e.g., microbeads attached to cells, liposome-coated micro-beads,liposome-coated magnetic beads, or the like). Beads may includemoieties/molecules covalently or non-covalently attached, such asfluorescent labels, proteins, carbohydrates, antigens, small moleculesignaling moieties, or other chemical/biological species capable of usein an assay. Lipid nanorafts have been described, for example, inRitchie et al. (2009) “Reconstitution of Membrane Proteins inPhospholipid Bilayer Nanodiscs,” Methods Enzymol., 464:211-231.

As used herein, the term “cell” is used interchangeably with the term“biological cell.” Non-limiting examples of biological cells includeeukaryotic cells, plant cells, animal cells, such as mammalian cells,reptilian cells, avian cells, fish cells, or the like, prokaryoticcells, bacterial cells, fungal cells, protozoan cells, or the like,cells dissociated from a tissue, such as muscle, cartilage, fat, skin,liver, lung, neural tissue, and the like, immunological cells, such as Tcells, B cells, natural killer cells, macrophages, and the like, embryos(e.g., zygotes), oocytes, ova, sperm cells, hybridomas, cultured cells,cells from a cell line, cancer cells, infected cells, transfected and/ortransformed cells, reporter cells, and the like. A mammalian cell canbe, for example, from a human, a mouse, a rat, a horse, a goat, a sheep,a cow, a primate, or the like.

A colony of biological cells is “clonal” if all of the living cells inthe colony that are capable of reproducing are daughter cells derivedfrom a single parent cell. In certain embodiments, all the daughtercells in a colonal colony are derived from the single parent cell by nomore than 10 divisions. In other embodiments, all the daughter cells ina colonal colony are derived from the single parent cell by no more than14 divisions. In other embodiments, all the daughter cells in a colonalcolony are derived from the single parent cell by no more than 17divisions. In other embodiments, all the daughter cells in a colonalcolony are derived from the single parent cell by no more than 20divisions. The term “clonal cells” refers to cells of the same clonalcolony.

As used herein, a “colony” of biological cells refers to 2 or more cells(e.g. about 2 to about 20, about 4 to about 40, about 6 to about 60,about 8 to about 80, about 10 to about 100, about 20 about 200, about 40about 400, about 60 about 600, about 80 about 800, about 100 about 1000,or greater than 1000 cells).

As used herein, the term “maintaining (a) cell(s)” refers to providingan environment comprising both fluidic and gaseous components and,optionally a surface, that provides the conditions necessary to keep thecells viable and/or expanding.

A “component” of a fluidic medium is any chemical or biochemicalmolecule present in the medium, including solvent molecules, ions, smallmolecules, antibiotics, nucleotides and nucleosides, nucleic acids,amino acids, peptides, proteins, sugars, carbohydrates, lipids, fattyacids, cholesterol, metabolites, or the like.

As used herein in reference to a fluidic medium, “diffuse” and“diffusion” refer to thermodynamic movement of a component of thefluidic medium down a concentration gradient.

The phrase “flow of a medium” means bulk movement of a fluidic mediumprimarily due to any mechanism other than diffusion. For example, flowof a medium can involve movement of the fluidic medium from one point toanother point due to a pressure differential between the points. Suchflow can include a continuous, pulsed, periodic, random, intermittent,or reciprocating flow of the liquid, or any combination thereof. Whenone fluidic medium flows into another fluidic medium, turbulence andmixing of the media can result.

The phrase “substantially no flow” refers to a rate of flow of a fluidicmedium that, averaged over time, is less than the rate of diffusion ofcomponents of a material (e.g., an analyte of interest) into or withinthe fluidic medium. The rate of diffusion of components of such amaterial can depend on, for example, temperature, the size of thecomponents, and the strength of interactions between the components andthe fluidic medium.

As used herein in reference to different regions within a microfluidicdevice, the phrase “fluidically connected” means that, when thedifferent regions are substantially filled with fluid, such as fluidicmedia, the fluid in each of the regions is connected so as to form asingle body of fluid. This does not mean that the fluids (or fluidicmedia) in the different regions are necessarily identical incomposition. Rather, the fluids in different fluidically connectedregions of a microfluidic device can have different compositions (e.g.,different concentrations of solutes, such as proteins, carbohydrates,ions, or other molecules) which are in flux as solutes move down theirrespective concentration gradients and/or fluids flow through thedevice.

A microfluidic (or nanofluidic) device can comprise “swept” regions and“unswept” regions. As used herein, a “swept” region is comprised of oneor more fluidically interconnected circuit elements of a microfluidiccircuit, each of which experiences a flow of medium when fluid isflowing through the microfluidic circuit. The circuit elements of aswept region can include, for example, regions, channels, and all orparts of chambers. As used herein, an “unswept” region is comprised ofone or more fluidically interconnected circuit element of a microfluidiccircuit, each of which experiences substantially no flux of fluid whenfluid is flowing through the microfluidic circuit. An unswept region canbe fluidically connected to a swept region, provided the fluidicconnections are structured to enable diffusion but substantially no flowof media between the swept region and the unswept region. Themicrofluidic device can thus be structured to substantially isolate anunswept region from a flow of medium in a swept region, while enablingsubstantially only diffusive fluidic communication between the sweptregion and the unswept region. For example, a flow channel of amicrofluidic device is an example of a swept region while an isolationregion (described in further detail below) of a microfluidic device isan example of an unswept region.

As used herein, a “flow path” refers to one or more fluidicallyconnected circuit elements (e.g. channel(s), region(s), chamber(s) andthe like) that define, and are subject to, the trajectory of a flow ofmedium. A flow path is thus an example of a swept region of amicrofluidic device. Other circuit elements (e.g., unswept regions) maybe fluidically connected with the circuit elements that comprise theflow path without being subject to the flow of medium in the flow path.

As used herein, the “clear aperture” of a lens (or lens assembly) is thediameter or size of the portion of the lens (or lens assembly) that canbe used for its intended purpose. Due to manufacturing constraints, itis virtually impossible to produce a clear aperture equal to the actualphysical diameter of the lens (or lens assembly).

As used herein, the term “active area” refers to the portion of an imagesensor or structured light modulator that can be used, respectively, toimage or provide structured light to a field of view in a particularoptical apparatus. The active area is subject to constraints of theoptical apparatus, such as the aperture stop of the light path withinthe optical apparatus. Although the active area corresponds to atwo-dimensional surface, the measurement of active area typicallycorresponds to the length of a diagonal line through opposing corners ofa square having the same area.

As used herein, an “image light beam” is an electromagnetic wave that isreflected or emitted from a device surface, a micro-object, or a fluidicmedium that is being viewed by an optical apparatus. The device can be amicrofluidic device, such as a light-actuated microfluidic (LAMF)device. The micro-object and the fluidic medium can be located withinsuch a microfluidic device.

As used herein: μm means micrometer, μm³ means cubic micrometer, pLmeans picoliter, nL means nanoliter, and μL (or uL) means microliter.

Methods of loading. Loading of biological micro-objects or micro-objectssuch as, but not limited to, beads, can involve the use of fluid flow,gravity, a dielectrophoresis (DEP) force, electrowetting, a magneticforce, or any combination thereof as described herein. The DEP force canbe optically actuated, such as by an optoelectronic tweezers (OET)configuration and/or electrically actuated, such as by activation ofelectrodes/electrode regions in a temporal/spatial pattern. Similarly,electrowetting force may be optically actuated, such as by anopto-electro wetting (OEW) configuration and/or electrically actuated,such as by activation of electrodes/electrode regions in a temporalspatial pattern.

The present disclosure relates to optical apparatuses, systems andmethods for viewing and manipulating micro-objects. In particular, thedisclosure relates to an optical apparatus for viewing and manipulatingmicro-objects in a microfluidic device, such as a light-actuatedmicrofluidic device, and related systems and methods.

Disclosed herein is an optical apparatus for viewing and/or manipulatingmicro-objects in a microfluidic device. The optical apparatus isconfigured to perform imaging, analysis and manipulation of one or moremicro-objects within an enclosure of the microfluidic device. Theoptical apparatus can comprise a first light source, a structured lightmodulator, a first tube lens, an objective lens, a dichroic beamsplitter, a second tube lens, and an image sensor. The structured lightmodulator is configured to receive unstructured light beams from thefirst light source and transmit structured light beams for imagingand/or selectively activating one or more of a plurality ofdielectrophoresis (DEP) electrodes on a surface of a substrate of themicrofluidic device, including any of the light-actuated microfluidicdevices discussed herein. The first tube lens is configured to capturethe structured light beams from the structured light modulator. Theobjective lens is configured to image a field of view comprising atleast a portion of the enclosure of the microfluidic device. Thedichroic beam splitter is configured to reflect (or transmit) lightbeams from the first tube lens to the objective lens and to transmit (orreflect) image light beams received from the objective lens to thesecond tube lens. The second tube lens is configured to receive theimage light beams from the dichroic beam splitter and to transmit theimage light beams to an image sensor. The image sensor is configured toreceive the image light beams from the second tube lens and generatetherefrom an image of the field of view.

Disclosed herein is a system for observing and manipulatingmicro-objects. The system can comprise a microfluidic device and anoptical apparatus for imaging and/or manipulating micro-objects in themicrofluidic device. The microfluidic device can comprise an enclosurehaving a substrate. The microfluidic device can further comprise a flowregion and a plurality of sequestration pens, each of which arefluidically connected to the flow region. The substrate can comprise asurface and a plurality of dielectrophoresis (DEP) electrodes on orcomprised by the surface. The microfluidic device can further comprise acover, which may comprises a ground electrode that is transparent tovisible light. The details of such microfluidic apparatus are describedelsewhere herein and in the art. See, e.g., International PatentApplication Publication No. WO 2016/094507, filed Dec. 9, 2015; U.S.Pat. No. 9,403,172, filed Oct. 10, 2013; and International PatentApplication Publication No. WO 2014/074367, filed Oct. 30, 2013. Theoptical apparatus can be configured to perform imaging, analysis andmanipulation of one or more micro-objects within the enclosure. Theoptical apparatus can comprise a first light source, a structured lightmodulator, a first tube lens and a second tube lens, an objective lens,a dichroic beam splitter and an image sensor. The structured lightmodulator can be configured to receive light from the first light sourceand transmit structured light beams to selectively image and/or activateone or more of the plurality of DEP electrodes on the surface of thesubstrate of the microfluidic device. The first tube lens can beconfigured to capture light from the structured light modulator. Theobjective lens can be configured to image a field of view comprising atleast a portion of the flow region and/or a portion of the plurality ofsequestration pens within the microfluidic device. The dichroic beamsplitter can be configured to reflect or transmit structured light beamsfrom the first tube lens to the objective lens and to transmit orreflect image light beams received from the objective lens to a secondtube lens. The second tube lens is configured to receive the image lightbeams from the dichroic beam splitter and to transmit the image lightbeams to an image sensor. The image sensor is configured to receive theimage light beams and generate therefrom an image of the field of view.

Disclosed herein are microfluidic devices and systems for operating andobserving such devices. FIG. 1A illustrates an example of a microfluidicdevice 100 and a system 150 which can be used for the screening anddetection of antibody-producing cells that secrete antibodies that bind(e.g., specifically bind) to an antigen of interest. A perspective viewof the microfluidic device 100 is shown having a partial cut-away of itscover 110 to provide a partial view into the microfluidic device 100.The microfluidic device 100 generally comprises a microfluidic circuit120 comprising a flow path 106 through which a fluidic medium 180 canflow, optionally carrying one or more micro-objects (not shown) intoand/or through the microfluidic circuit 120. Although a singlemicrofluidic circuit 120 is illustrated in FIG. 1A, suitablemicrofluidic devices can include a plurality (e.g., 2 or 3) of suchmicrofluidic circuits. Regardless, the microfluidic device 100 can beconfigured to be a nanofluidic device. In the embodiment illustrated inFIG. 1A, the microfluidic circuit 120 comprises a plurality ofmicrofluidic sequestration pens 124, 126, 128, and 130, each having anopening (e.g., a single opening) in fluidic communication with flow path106. As discussed further below, the microfluidic sequestration penscomprise various features and structures that have been optimized forretaining micro-objects in the microfluidic device, such as microfluidicdevice 100, even when a medium 180 is flowing through the flow path 106.Before turning to the foregoing, however, a brief description ofmicrofluidic device 100 and system 150 is provided.

As generally illustrated in FIG. 1A, the microfluidic circuit 120 isdefined by an enclosure 102. Although the enclosure 102 can bephysically structured in different configurations, in the example shownin FIG. 1A the enclosure 102 is depicted as comprising a supportstructure 104 (e.g., a base), a microfluidic circuit structure 108, anda cover 110. The support structure 104, microfluidic circuit structure108, and cover 110 can be attached to each other. For example, themicrofluidic circuit structure 108 can be disposed on an inner surface109 of the support structure 104, and the cover 110 can be disposed overthe microfluidic circuit structure 108. Together with the supportstructure 104 and cover 110, the microfluidic circuit structure 108 candefine the elements of the microfluidic circuit 120.

The support structure 104 can be at the bottom and the cover 110 at thetop of the microfluidic circuit 120 as illustrated in FIG. 1A.Alternatively, the support structure 104 and the cover 110 can beconfigured in other orientations. For example, the support structure 104can be at the top and the cover 110 at the bottom of the microfluidiccircuit 120. Regardless, there can be one or more ports 107 eachcomprising a passage into or out of the enclosure 102. Examples of apassage include a valve, a gate, a pass-through hole, or the like. Asillustrated, port 107 is a pass-through hole created by a gap in themicrofluidic circuit structure 108. However, the port 107 can besituated in other components of the enclosure 102, such as the cover110. Only one port 107 is illustrated in FIG. 1A but the microfluidiccircuit 120 can have two or more ports 107. For example, there can be afirst port 107 that functions as an inlet for fluid entering themicrofluidic circuit 120, and there can be a second port 107 thatfunctions as an outlet for fluid exiting the microfluidic circuit 120.Whether a port 107 function as an inlet or an outlet can depend upon thedirection that fluid flows through flow path 106.

The support structure 104 can comprise one or more electrodes (notshown) and a substrate or a plurality of interconnected substrates. Forexample, the support structure 104 can comprise one or moresemiconductor substrates, each of which is electrically connected to anelectrode (e.g., all or a subset of the semiconductor substrates can beelectrically connected to a single electrode). The support structure 104can further comprise a printed circuit board assembly (“PCBA”). Forexample, the semiconductor substrate(s) can be mounted on a PCBA.

The microfluidic circuit structure 108 can define circuit elements ofthe microfluidic circuit 120. Such circuit elements can comprise spacesor regions that can be fluidly interconnected when microfluidic circuit120 is filled with fluid, such as flow regions (which may include or beone or more flow channels), chambers, pens, traps, and the like. In themicrofluidic circuit 120 illustrated in FIG. 1A, the microfluidiccircuit structure 108 comprises a frame 114 and a microfluidic circuitmaterial 116. The frame 114 can partially or completely enclose themicrofluidic circuit material 116. The frame 114 can be, for example, arelatively rigid structure substantially surrounding the microfluidiccircuit material 116. For example, the frame 114 can comprise a metalmaterial.

The microfluidic circuit material 116 can be patterned with cavities orthe like to define circuit elements and interconnections of themicrofluidic circuit 120. The microfluidic circuit material 116 cancomprise a flexible material, such as a flexible polymer (e.g. rubber,plastic, elastomer, silicone, polydimethylsiloxane (“PDMS”), or thelike), which can be gas permeable. Other examples of materials that cancompose microfluidic circuit material 116 include molded glass, anetchable material such as silicone (e.g. photo-patternable silicone or“PPS”), photo-resist (e.g., SU8), or the like. In some embodiments, suchmaterials—and thus the microfluidic circuit material 116—can be rigidand/or substantially impermeable to gas. Regardless, microfluidiccircuit material 116 can be disposed on the support structure 104 andinside the frame 114.

The cover 110 can be an integral part of the frame 114 and/or themicrofluidic circuit material 116. Alternatively, the cover 110 can be astructurally distinct element, as illustrated in FIG. 1A. The cover 110can comprise the same or different materials than the frame 114 and/orthe microfluidic circuit material 116. Similarly, the support structure104 can be a separate structure from the frame 114 or microfluidiccircuit material 116 as illustrated, or an integral part of the frame114 or microfluidic circuit material 116. Likewise, the frame 114 andmicrofluidic circuit material 116 can be separate structures as shown inFIG. 1A or integral portions of the same structure.

In some embodiments, the cover 110 can comprise a rigid material. Therigid material may be glass or a material with similar properties. Insome embodiments, the cover 110 can comprise a deformable material. Thedeformable material can be a polymer, such as PDMS. In some embodiments,the cover 110 can comprise both rigid and deformable materials. Forexample, one or more portions of cover 110 (e.g., one or more portionspositioned over sequestration pens 124, 126, 128, 130) can comprise adeformable material that interfaces with rigid materials of the cover110. In some embodiments, the cover 110 can further include one or moreelectrodes. The one or more electrodes can comprise a conductive oxide,such as indium-tin-oxide (ITO), which may be coated on glass or asimilarly insulating material. Alternatively, the one or more electrodescan be flexible electrodes, such as single-walled nanotubes,multi-walled nanotubes, nanowires, clusters of electrically conductivenanoparticles, or combinations thereof, embedded in a deformablematerial, such as a polymer (e.g., PDMS). Flexible electrodes that canbe used in microfluidic devices have been described, for example, inU.S. 2012/0325665 (Chiou et al.), the contents of which are incorporatedherein by reference. In some embodiments, the cover 110 can be modified(e.g., by conditioning all or part of a surface that faces inward towardthe microfluidic circuit 120) to support cell adhesion, viability and/orgrowth. The modification may include a coating of a synthetic or naturalpolymer. In some embodiments, the cover 110 and/or the support structure104 can be transparent to light. The cover 110 may also include at leastone material that is gas permeable (e.g., PDMS or PPS).

FIG. 1A also shows a system 150 for operating and controllingmicrofluidic devices, such as microfluidic device 100. System 150includes an electrical power source 192, an imaging device 194(incorporated within imaging module 164, where device 194 is notillustrated in FIG. 1A, per se), and a tilting device 190 (incorporatedwithin tilting module 166, where device 190 is not illustrated in FIG.1).

The electrical power source 192 can provide electric power to themicrofluidic device 100 and/or tilting device 190, providing biasingvoltages or currents as needed. The electrical power source 192 can, forexample, comprise one or more alternating current (AC) and/or directcurrent (DC) voltage or current sources. The imaging device 194 (part ofimaging module 164, discussed below) can comprise a device, such as adigital camera, for capturing images inside microfluidic circuit 120. Insome instances, the imaging device 194 further comprises a detectorhaving a fast frame rate and/or high sensitivity (e.g. for low lightapplications). The imaging device 194 can also include a mechanism fordirecting stimulating radiation and/or light beams into the microfluidiccircuit 120 and collecting radiation and/or light beams reflected oremitted from the microfluidic circuit 120 (or micro-objects containedtherein). The emitted light beams may be in the visible spectrum andmay, e.g., include fluorescent emissions. The reflected light beams mayinclude reflected emissions originating from an LED or a wide spectrumlamp, such as a mercury lamp (e.g. a high pressure mercury lamp) or aXenon arc lamp. As discussed with respect to FIG. 3B, the imaging device194 may further include a microscope (or an optical apparatus), whichmay or may not include an eyepiece.

System 150 further comprises a tilting device 190 (part of tiltingmodule 166, discussed below) configured to rotate a microfluidic device100 about one or more axes of rotation. In some embodiments, the tiltingdevice 190 is configured to support and/or hold the enclosure 102comprising the microfluidic circuit 120 about at least one axis suchthat the microfluidic device 100 (and thus the microfluidic circuit 120)can be held in a level orientation (i.e. at 0° relative to x- andy-axes), a vertical orientation (i.e. at 90° relative to the x-axisand/or the y-axis), or any orientation therebetween. The orientation ofthe microfluidic device 100 (and the microfluidic circuit 120) relativeto an axis is referred to herein as the “tilt” of the microfluidicdevice 100 (and the microfluidic circuit 120). For example, the tiltingdevice 190 can tilt the microfluidic device 100 at 0.1°, 0.2°, 0.3°,0.4°, 0.5°, 0.6°, 0.7°, 0.8°, 0.9°, 1°, 2°, 3°, 4°, 5°, 10°, 15°, 20°,25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 90° relativeto the x-axis or any degree therebetween. The level orientation (andthus the x- and y-axes) is defined as normal to a vertical axis definedby the force of gravity. The tilting device can also tilt themicrofluidic device 100 (and the microfluidic circuit 120) to any degreegreater than 90° relative to the x-axis and/or y-axis, or tilt themicrofluidic device 100 (and the microfluidic circuit 120) 180° relativeto the x-axis or the y-axis in order to fully invert the microfluidicdevice 100 (and the microfluidic circuit 120). Similarly, in someembodiments, the tilting device 190 tilts the microfluidic device 100(and the microfluidic circuit 120) about an axis of rotation defined byflow path 106 or some other portion of microfluidic circuit 120.

In some instances, the microfluidic device 100 is tilted into a verticalorientation such that the flow path 106 is positioned above or below oneor more sequestration pens. The term “above” as used herein denotes thatthe flow path 106 is positioned higher than the one or moresequestration pens on a vertical axis defined by the force of gravity(i.e. an object in a sequestration pen above a flow path 106 would havea higher gravitational potential energy than an object in the flowpath). The term “below” as used herein denotes that the flow path 106 ispositioned lower than the one or more sequestration pens on a verticalaxis defined by the force of gravity (i.e. an object in a sequestrationpen below a flow path 106 would have a lower gravitational potentialenergy than an object in the flow path).

In some instances, the tilting device 190 tilts the microfluidic device100 about an axis that is parallel to the flow path 106. Moreover, themicrofluidic device 100 can be tilted to an angle of less than 90° suchthat the flow path 106 is located above or below one or moresequestration pens without being located directly above or below thesequestration pens. In other instances, the tilting device 190 tilts themicrofluidic device 100 about an axis perpendicular to the flow path106. In still other instances, the tilting device 190 tilts themicrofluidic device 100 about an axis that is neither parallel norperpendicular to the flow path 106.

System 150 can further include a media source 178. The media source 178(e.g., a container, reservoir, or the like) can comprise multiplesections or containers, each for holding a different fluidic medium 180.Thus, the media source 178 can be a device that is outside of andseparate from the microfluidic device 100, as illustrated in FIG. 1A.Alternatively, the media source 178 can be located in whole or in partinside the enclosure 102 of the microfluidic device 100. For example,the media source 178 can comprise reservoirs that are part of themicrofluidic device 100.

FIG. 1A also illustrates simplified block diagram depictions of examplesof control and monitoring equipment 152 that constitute part of system150 and can be utilized in conjunction with a microfluidic device 100.As shown, examples of such control and monitoring equipment 152 includea master controller 154, which can control other control and monitoringequipment, such as a media module 160 for controlling the media source178, a motive module 162 for controlling movement and/or selection ofmicro-objects (not shown) and/or medium (e.g., droplets of medium) inthe microfluidic circuit 120, an imaging module 164 for controlling animaging device 194 (e.g., a camera, microscope, light source or anycombination thereof) for capturing images (e.g., digital images), and atilting module 166 for controlling a tilting device 190. The controlequipment 152 can also include other modules 168 for controlling,monitoring, or performing other functions with respect to themicrofluidic device 100. As shown, the equipment 152 can further includea display device 170 and an input/output device 172.

The master controller 154 can comprise a control module 156 and adigital memory 158. The control module 156 can comprise, for example, adigital processor configured to operate in accordance with machineexecutable instructions (e.g., software, firmware, source code, or thelike) stored as non-transitory data or signals in the memory 158.Alternatively, or in addition, the control module 156 can comprisehardwired digital circuitry and/or analog circuitry. The media module160, motive module 162, imaging module 164, tilting module 166, and/orother modules 168 can be similarly configured. Thus, functions,processes acts, actions, or steps of a process discussed herein as beingperformed with respect to the microfluidic device 100 or any othermicrofluidic apparatus can be performed by any one or more of the mastercontroller 154, media module 160, motive module 162, imaging module 164,tilting module 166, and/or other modules 168 configured as discussedabove. Similarly, the master controller 154, media module 160, motivemodule 162, imaging module 164, tilting module 166, and/or other modules168 may be communicatively coupled to transmit and receive data used inany function, process, act, action or step discussed herein.

The media module 160 controls the media source 178. For example, themedia module 160 can control the media source 178 to input a selectedfluidic medium 180 into the enclosure 102 (e.g., through an inlet port107). The media module 160 can also control removal of media from theenclosure 102 (e.g., through an outlet port (not shown)). One or moremedia can thus be selectively input into and removed from themicrofluidic circuit 120. The media module 160 can also control the flowof fluidic medium 180 in the flow path 106 inside the microfluidiccircuit 120. For example, in some embodiments media module 160 stops theflow of media 180 in the flow path 106 and through the enclosure 102prior to the tilting module 166 causing the tilting device 190 to tiltthe microfluidic device 100 to a desired angle of incline.

The motive module 162 can be configured to control selection, trapping,and movement of micro-objects (not shown) in the microfluidic circuit120. As discussed below with respect to FIGS. 1B and 1C, the enclosure102 can comprise a dielectrophoresis (DEP), optoelectronic tweezers(OET), and/or opto-electrowetting (OEW) configuration (not shown in FIG.1A), and the motive module 162 can control the activation of electrodesand/or transistors (e.g., phototransistors) to select and movemicro-objects (not shown) and/or droplets of medium (not shown) in theflow path 106 and/or sequestration pens 124, 126, 128, 130.

The imaging module 164 can control the imaging device 194. For example,the imaging module 164 can receive and process image data from theimaging device 194. Image data from the imaging device 194 can compriseany type of information captured by the imaging device 194 (e.g., thepresence or absence of micro-objects, droplets of medium, accumulationof label, such as fluorescent label, etc.). Using the informationcaptured by the imaging device 194, the imaging module 164 can furthercalculate the position of objects (e.g., micro-objects, droplets ofmedium) and/or the rate of motion of such objects within themicrofluidic device 100.

The tilting module 166 can control the tilting motions of tilting device190. Alternatively, or in addition, the tilting module 166 can controlthe tilting rate and timing to optimize transfer of micro-objects to theone or more sequestration pens via gravitational forces. The tiltingmodule 166 is communicatively coupled with the imaging module 164 toreceive data describing the motion of micro-objects and/or droplets ofmedium in the microfluidic circuit 120. Using this data, the tiltingmodule 166 may adjust the tilt of the microfluidic circuit 120 in orderto adjust the rate at which micro-objects and/or droplets of medium movein the microfluidic circuit 120. The tilting module 166 may also usethis data to iteratively adjust the position of a micro-object and/ordroplet of medium in the microfluidic circuit 120.

In the example shown in FIG. 1A, the microfluidic circuit 120 isillustrated as comprising a microfluidic channel 122 and sequestrationpens 124, 126, 128, 130. Each pen comprises a single opening to channel122, but otherwise is enclosed such that the pens can substantiallyisolate micro-objects inside the pen from fluidic medium 180 and/ormicro-objects in the flow path 106 of channel 122 or in other pens. Thewalls of the sequestration pen extend from the inner surface 109 of thebase to the inside surface of the cover 110 to provide enclosure. Theopening of the pen to the channel 122 is oriented at an angle to theflow 106 of fluidic medium 180 such that flow 106 is not directed intothe pens. The flow may be tangential or orthogonal to the plane of theopening of the pen. In some instances, pens 124, 126, 128, 130 areconfigured to physically corral one or more micro-objects within themicrofluidic circuit 120. Sequestration pens in accordance with thepresent invention can comprise various shapes, surfaces and featuresthat are optimized for use with DEP, OET, fluid flow, and/orgravitational forces, as will be discussed and shown in detail below.

The microfluidic circuit 120 may comprise any number of microfluidicsequestration pens. Although five sequestration pens are shown,microfluidic circuit 120 may have fewer or more sequestration pens. Asshown, microfluidic sequestration pens 124, 126, 128, and 130 ofmicrofluidic circuit 120 each comprise differing features and shapeswhich may provide one or more benefits useful in screeningantibody-producing cells, such as isolating one antibody-producing cellfrom another antibody-producing cell. Microfluidic sequestration pens124, 126, 128, and 130 may provide other benefits, such as facilitatingsingle-cell loading and/or growth of colonies (e.g., clonal colonies) ofantibody-producing cells. In some embodiments, the microfluidic circuit120 comprises a plurality of identical microfluidic sequestration pens.

In some embodiments, the microfluidic circuit 120 comprises a pluralityof microfluidic sequestration pens, wherein two or more of thesequestration pens comprise differing structures and/or features whichprovide differing benefits for screening antibody-producing cells.Microfluidic devices useful for screening antibody-producing cells mayinclude any of the sequestration pens 124, 126, 128, and 130 orvariations thereof, and/or may include pens configured like those shownin FIGS. 2B, 2C, 2D, 2E and 2F, as discussed below.

In the embodiment illustrated in FIG. 1A, a single channel 122 and flowpath 106 is shown. However, other embodiments may contain multiplechannels 122, each configured to comprise a flow path 106. Themicrofluidic circuit 120 further comprises an inlet valve or port 107 influid communication with the flow path 106 and fluidic medium 180,whereby fluidic medium 180 can access channel 122 via the inlet port107. In some instances, the flow path 106 comprises a single path. Insome instances, the single path is arranged in a zigzag pattern wherebythe flow path 106 travels across the microfluidic device 100 two or moretimes in alternating directions.

In some instances, microfluidic circuit 120 comprises a plurality ofparallel channels 122 and flow paths 106, wherein the fluidic medium 180within each flow path 106 flows in the same direction. In someinstances, the fluidic medium within each flow path 106 flows in atleast one of a forward or reverse direction. In some instances, aplurality of sequestration pens is configured (e.g., relative to achannel 122) such that the sequestration pens can be loaded with targetmicro-objects in parallel.

In some embodiments, microfluidic circuit 120 further comprises one ormore micro-object traps 132. The traps 132 are generally formed in awall forming the boundary of a channel 122, and may be positionedopposite an opening of one or more of the microfluidic sequestrationpens 124, 126, 128, 130. In some embodiments, the traps 132 areconfigured to receive or capture a single micro-object from the flowpath 106. In some embodiments, the traps 132 are configured to receiveor capture a plurality of micro-objects from the flow path 106. In someinstances, the traps 132 comprise a volume approximately equal to thevolume of a single target micro-object.

The traps 132 may further comprise an opening which is configured toassist the flow of targeted micro-objects into the traps 132. In someinstances, the traps 132 comprise an opening having a height and widththat is approximately equal to the dimensions of a single targetmicro-object, whereby larger micro-objects are prevented from enteringinto the micro-object trap. The traps 132 may further comprise otherfeatures configured to assist in retention of targeted micro-objectswithin the trap 132. In some instances, the trap 132 is aligned with andsituated on the opposite side of a channel 122 relative to the openingof a microfluidic sequestration pen, such that upon tilting themicrofluidic device 100 about an axis parallel to the channel 122, thetrapped micro-object exits the trap 132 at a trajectory that causes themicro-object to fall into the opening of the sequestration pen. In someinstances, the trap 132 comprises a side passage 134 that is smallerthan the target micro-object in order to facilitate flow through thetrap 132 and thereby increase the likelihood of capturing a micro-objectin the trap 132.

In some embodiments, dielectrophoretic (DEP) forces are applied acrossthe fluidic medium 180 (e.g., in the flow path and/or in thesequestration pens) via one or more electrodes (not shown) tomanipulate, transport, separate and sort micro-objects located therein.For example, in some embodiments, DEP forces are applied to one or moreportions of microfluidic circuit 120 in order to transfer a singlemicro-object from the flow path 106 into a desired microfluidicsequestration pen. In some embodiments, DEP forces are used to prevent amicro-object within a sequestration pen (e.g., sequestration pen 124,126, 128, or 130) from being displaced therefrom. Further, in someembodiments, DEP forces are used to selectively remove a micro-objectfrom a sequestration pen that was previously collected in accordancewith the teachings of the instant invention. In some embodiments, theDEP forces comprise optoelectronic tweezer (OET) forces.

In other embodiments, optoelectrowetting (OEW) forces are applied to oneor more positions in the support structure 104 (and/or the cover 110) ofthe microfluidic device 100 (e.g., positions helping to define the flowpath and/or the sequestration pens) via one or more electrodes (notshown) to manipulate, transport, separate and sort droplets located inthe microfluidic circuit 120. For example, in some embodiments, OEWforces are applied to one or more positions in the support structure 104(and/or the cover 110) in order to transfer a single droplet from theflow path 106 into a desired microfluidic sequestration pen. In someembodiments, OEW forces are used to prevent a droplet within asequestration pen (e.g., sequestration pen 124, 126, 128, or 130) frombeing displaced therefrom. Further, in some embodiments, OEW forces areused to selectively remove a droplet from a sequestration pen that waspreviously collected in accordance with the teachings of the instantinvention.

In some embodiments, DEP and/or OEW forces are combined with otherforces, such as flow and/or gravitational force, so as to manipulate,transport, separate and sort micro-objects and/or droplets within themicrofluidic circuit 120. For example, the enclosure 102 can be tilted(e.g., by tilting device 190) to position the flow path 106 andmicro-objects located therein above the microfluidic sequestration pens,and the force of gravity can transport the micro-objects and/or dropletsinto the pens. In some embodiments, the DEP and/or OEW forces can beapplied prior to the other forces. In other embodiments, the DEP and/orOEW forces can be applied after the other forces. In still otherinstances, the DEP and/or OEW forces can be applied at the same time asthe other forces or in an alternating manner with the other forces.

FIGS. 1B, 1C, and 2A-2H illustrates various embodiments of microfluidicdevices that can be used in the practice of the present invention. FIG.1B depicts an embodiment in which the microfluidic device 200 isconfigured as an optically-actuated electrokinetic device. A variety ofoptically-actuated electrokinetic devices are known in the art,including devices having an optoelectronic tweezer (OET) configurationand devices having an opto-electrowetting (OEW) configuration. Examplesof suitable OET configurations are illustrated in the following U.S.patent documents, each of which is incorporated herein by reference inits entirety: U.S. Pat. No. RE 44,711 (Wu et al.) (originally issued asU.S. Pat. No. 7,612,355); U.S. Pat. No. 7,956,339 (Ohta et al.); U.S.Pat. No. 9,403,172 (Wu et al.); and U.S. Patent Application PublicationNo. 20160184821 (Hobbs et al.). Examples of OEW configurations areillustrated in U.S. Pat. No. 6,958,132 (Chiou et al.); U.S. PatentApplication Publication No. 2012/0024708 (Chiou et al.); and U.S. Pat.No. 9,815,056 (Wu et al.), each of which is incorporated by referenceherein in its entirety. Yet another example of an optically-actuatedelectrokinetic device includes a combined OET/OEW configuration,examples of which are shown in U.S. Patent Publication Nos. 20150306598(Khandros et al.) and 20150306599 (Khandros et al.) and theircorresponding PCT Publications WO2015/164846 and WO2015/164847, all ofwhich are incorporated herein by reference in their entirety.

Examples of microfluidic devices having pens in which antibody-producingcells can be placed, cultured, monitored, and/or screened have beendescribed, for example, in U.S. Patent Application Publication Nos.20140116881 (Chapman et al.), 20150151298 (Hobbs et al.), and20150165436 (Chapman et al.), each of which is incorporated herein byreference in its entirety. Each of the foregoing applications furtherdescribes microfluidic devices configured to produce dielectrophoretic(DEP) forces, such as optoelectronic tweezers (OET) or configured toprovide opto-electro wetting (OEW). For example, the optoelectronictweezers device illustrated in FIG. 2 of U.S. Patent ApplicationPublication Nos. 20140116881 (Chapman et al.) is an example of a devicethat can be utilized in embodiments of the present invention to selectand move an individual biological micro-object or a group of biologicalmicro-objects.

Microfluidic device motive configurations. As described above, thecontrol and monitoring equipment of the system can comprise a motivemodule for selecting and moving objects, such as micro-objects ordroplets, in the microfluidic circuit of a microfluidic device. Themicrofluidic device can have a variety of motive configurations,depending upon the type of object being moved and other considerations.For example, a dielectrophoresis (DEP) configuration can be utilized toselect and move micro-objects in the microfluidic circuit. Thus, thesupport structure 104 and/or cover 110 of the microfluidic device 100can comprise a DEP configuration for selectively inducing DEP forces onmicro-objects in a fluidic medium 180 in the microfluidic circuit 120and thereby select, capture, and/or move individual micro-objects orgroups of micro-objects. Alternatively, the support structure 104 and/orcover 110 of the microfluidic device 100 can comprise an electrowetting(EW) configuration for selectively inducing EW forces on droplets in afluidic medium 180 in the microfluidic circuit 120 and thereby select,capture, and/or move individual droplets or groups of droplets.

One example of a microfluidic device 200 comprising a DEP configurationis illustrated in FIGS. 1B and 1C. While for purposes of simplicityFIGS. 1B and 1C show a side cross-sectional view and a topcross-sectional view, respectively, of a portion of an enclosure 102 ofthe microfluidic device 200 having an open region/chamber 202, it shouldbe understood that the region/chamber 202 may be part of a fluidiccircuit element having a more detailed structure, such as a growthchamber, a sequestration pen, a flow region, or a flow channel.Furthermore, the microfluidic device 200 may include other fluidiccircuit elements. For example, the microfluidic device 200 can include aplurality of growth chambers or sequestration pens and/or one or moreflow regions or flow channels, such as those described herein withrespect to microfluidic device 100. A DEP configuration may beincorporated into any such fluidic circuit elements of the microfluidicdevice 200, or select portions thereof. It should be further appreciatedthat any of the above or below described microfluidic device componentsand system components may be incorporated in and/or used in combinationwith the microfluidic device 200. For example, system 150 includingcontrol and monitoring equipment 152, described above, may be used withmicrofluidic device 200, including one or more of the media module 160,motive module 162, imaging module 164, tilting module 166, and othermodules 168.

As seen in FIG. 1B, the microfluidic device 200 includes a supportstructure 104 having a bottom electrode 204 and an electrode activationsubstrate 206 overlying the bottom electrode 204, and a cover 110 havinga top electrode 210, with the top electrode 210 spaced apart from thebottom electrode 204. The top electrode 210 and the electrode activationsubstrate 206 define opposing surfaces of the region/chamber 202. Amedium 180 contained in the region/chamber 202 thus provides a resistiveconnection between the top electrode 210 and the electrode activationsubstrate 206. A power source 212 configured to be connected to thebottom electrode 204 and the top electrode 210 and create a biasingvoltage between the electrodes, as required for the generation of DEPforces in the region/chamber 202, is also shown. The power source 212can be, for example, an alternating current (AC) power source.

In certain embodiments, the microfluidic device 200 illustrated in FIGS.1B and 1C can have an optically-actuated DEP configuration. Accordingly,changing patterns of light 218 from the light source 216, which may becontrolled by the motive module 162, can selectively activate anddeactivate changing patterns of DEP electrodes at regions 214 of theinner surface 208 of the electrode activation substrate 206.(Hereinafter the regions 214 of a microfluidic device having a DEPconfiguration are referred to as “DEP electrode regions.”) Asillustrated in FIG. 1C, a light pattern 218 directed onto the innersurface 208 of the electrode activation substrate 206 can illuminateselect DEP electrode regions 214 a (shown in white) in a pattern, suchas a square. The non-illuminated DEP electrode regions 214(cross-hatched) are hereinafter referred to as “dark” DEP electroderegions 214. The relative electrical impedance through the DEP electrodeactivation substrate 206 (i.e., from the bottom electrode 204 up to theinner surface 208 of the electrode activation substrate 206 whichinterfaces with the medium 180 in the flow region 106) is greater thanthe relative electrical impedance through the medium 180 in theregion/chamber 202 (i.e., from the inner surface 208 of the electrodeactivation substrate 206 to the top electrode 210 of the cover 110) ateach dark DEP electrode region 214. An illuminated DEP electrode region214 a, however, exhibits a reduced relative impedance through theelectrode activation substrate 206 that is less than the relativeimpedance through the medium 180 in the region/chamber 202 at eachilluminated DEP electrode region 214 a.

With the power source 212 activated, the foregoing DEP configurationcreates an electric field gradient in the fluidic medium 180 betweenilluminated DEP electrode regions 214 a and adjacent dark DEP electroderegions 214, which in turn creates local DEP forces that attract orrepel nearby micro-objects (not shown) in the fluidic medium 180. DEPelectrodes that attract or repel micro-objects in the fluidic medium 180can thus be selectively activated and deactivated at many different suchDEP electrode regions 214 at the inner surface 208 of the region/chamber202 by changing light patterns 218 projected from a light source 216into the microfluidic device 200. Whether the DEP forces attract orrepel nearby micro-objects can depend on such parameters as thefrequency of the power source 212 and the dielectric properties of themedium 180 and/or micro-objects (not shown).

The square pattern 220 of illuminated DEP electrode regions 214 aillustrated in FIG. 1C is an example only. Any pattern of the DEPelectrode regions 214 can be illuminated (and thereby activated) by thepattern of light 218 projected into the device 200, and the pattern ofilluminated/activated DEP electrode regions 214 can be repeatedlychanged by changing or moving the light pattern 218.

In some embodiments, the electrode activation substrate 206 can compriseor consist of a photoconductive material. In such embodiments, the innersurface 208 of the electrode activation substrate 206 can befeatureless. For example, the electrode activation substrate 206 cancomprise or consist of a layer of hydrogenated amorphous silicon(a-Si:H). The a-Si:H can comprise, for example, about 8% to 40% hydrogen(calculated as 100*the number of hydrogen atoms/the total number ofhydrogen and silicon atoms). The layer of a-Si:H can have a thickness ofabout 500 nm to about 2.0 microns. In such embodiments, the DEPelectrode regions 214 can be created anywhere and in any pattern on theinner surface 208 of the electrode activation substrate 206, inaccordance with the light pattern 218. The number and pattern of the DEPelectrode regions 214 thus need not be fixed, but can correspond to thelight pattern 218. Examples of microfluidic devices having a DEPconfiguration comprising a photoconductive layer such as discussed abovehave been described, for example, in U.S. Pat. No. RE 44,711 (Wu et al.)(originally issued as U.S. Pat. No. 7,612,355).

In other embodiments, the electrode activation substrate 206 cancomprise a substrate comprising a plurality of doped layers,electrically insulating layers (or regions), and electrically conductivelayers that form semiconductor integrated circuits, such as is known insemiconductor fields. For example, the electrode activation substrate206 can comprise a plurality of phototransistors, including, forexample, lateral bipolar phototransistors, each phototransistorcorresponding to a DEP electrode region 214. Alternatively, theelectrode activation substrate 206 can comprise electrodes (e.g.,conductive metal electrodes) controlled by phototransistor switches,with each such electrode corresponding to a DEP electrode region 214.The electrode activation substrate 206 can include a pattern of suchphototransistors or phototransistor-controlled electrodes. The pattern,for example, can be an array of substantially square phototransistors orphototransistor-controlled electrodes arranged in rows and columns, suchas shown in FIG. 2B. Alternatively, the pattern can be an array ofsubstantially hexagonal phototransistors or phototransistor-controlledelectrodes that form a hexagonal lattice. Regardless of the pattern,electric circuit elements can form electrical connections between theDEP electrode regions 214 at the inner surface 208 of the electrodeactivation substrate 206 and the bottom electrode 210, and thoseelectrical connections (i.e., phototransistors or electrodes) can beselectively activated and deactivated by the light pattern 218. When notactivated, each electrical connection can have high impedance such thatthe relative impedance through the electrode activation substrate 206(i.e., from the bottom electrode 204 to the inner surface 208 of theelectrode activation substrate 206 which interfaces with the medium 180in the region/chamber 202) is greater than the relative impedancethrough the medium 180 (i.e., from the inner surface 208 of theelectrode activation substrate 206 to the top electrode 210 of the cover110) at the corresponding DEP electrode region 214. When activated bylight in the light pattern 218, however, the relative impedance throughthe electrode activation substrate 206 is less than the relativeimpedance through the medium 180 at each illuminated DEP electroderegion 214, thereby activating the DEP electrode at the correspondingDEP electrode region 214 as discussed above. DEP electrodes that attractor repel micro-objects (not shown) in the medium 180 can thus beselectively activated and deactivated at many different DEP electroderegions 214 at the inner surface 208 of the electrode activationsubstrate 206 in the region/chamber 202 in a manner determined by thelight pattern 218.

Examples of microfluidic devices having electrode activation substratesthat comprise phototransistors have been described, for example, in U.S.Pat. No. 7,956,339 (Ohta et al.) (see, e.g., device 300 illustrated inFIGS. 21 and 22, and descriptions thereof), the entire contents of whichare incorporated herein by reference. Examples of microfluidic deviceshaving electrode activation substrates that comprise electrodescontrolled by phototransistor switches have been described, for example,in U.S. Pat. No. 9,403,172 (Short et al.) (see, e.g., devices 200, 400,500, 600, and 900 illustrated throughout the drawings, and descriptionsthereof).

In some embodiments of a DEP configured microfluidic device, the topelectrode 210 is part of a first wall (or cover 110) of the enclosure102, and the electrode activation substrate 206 and bottom electrode 204are part of a second wall (or support structure 104) of the enclosure102. The region/chamber 202 can be between the first wall and the secondwall. In other embodiments, the electrode 210 is part of the second wall(or support structure 104) and one or both of the electrode activationsubstrate 206 and/or the electrode 210 are part of the first wall (orcover 110). Moreover, the light source 216 can alternatively be used toilluminate the enclosure 102 from below.

With the microfluidic device 200 of FIGS. 1B-1C having a DEPconfiguration, the motive module 162 can select a micro-object (notshown) in the medium 180 in the region/chamber 202 by projecting a lightpattern 218 into the device 200 to activate a first set of one or moreDEP electrodes at DEP electrode regions 214 a of the inner surface 208of the electrode activation substrate 206 in a pattern (e.g., squarepattern 220) that surrounds and captures the micro-object. The motivemodule 162 can then move the captured micro-object by moving the lightpattern 218 relative to the device 200 to activate a second set of oneor more DEP electrodes at DEP electrode regions 214. Alternatively, thedevice 200 can be moved relative to the light pattern 218.

Regardless of the configuration of the microfluidic device 200, a powersource 212 can be used to provide a potential (e.g., an AC voltagepotential) that powers the electrical circuits of the microfluidicdevice 200. The power source 212 can be the same as, or a component of,the power source 192 referenced in FIG. 1. Power source 212 can beconfigured to provide an AC voltage and/or current to the top electrode210 and the bottom electrode 204. For an AC voltage, the power source212 can provide a frequency range and an average or peak power (e.g.,voltage or current) range sufficient to generate net DEP forces (orelectrowetting forces) strong enough to trap and move individualmicro-objects (not shown) in the region/chamber 202, as discussed above,and/or to change the wetting properties of the inner surface 208 of thesupport structure 104 (i.e., the dielectric layer and/or the hydrophobiccoating on the dielectric layer) in the region/chamber 202, as alsodiscussed above. Such frequency ranges and average or peak power rangersare known in the art. See, e.g., U.S. Pat. No. 6,958,132 (Chiou et al.),U.S. Pat. No. RE44,711 (Wu et al.) (originally issued as U.S. Pat. No.7,612,355), and US Patent Application Publication Nos. US2014/0124370(Short et al.), US2016/0184821 (Hobbs et al.), US2015/0306598 (Khandroset al.), and US2015/0306599 (Khandros et al.).

Sequestration pens. Non-limiting examples of generic sequestration pens224, 226, and 228 are shown within the microfluidic device 230 depictedin FIGS. 2A-2C. Each sequestration pen 224, 226, and 228 can comprise anisolation structure 232 defining an isolation region 240 and aconnection region 236 fluidically connecting the isolation region 240 toa channel 122. The connection region 236 can comprise a proximal opening234 to the channel 122 and a distal opening 238 to the isolation region240. The connection region 236 can be configured so that the maximumpenetration depth of a flow of a fluidic medium (not shown) flowing fromthe channel 122 into the sequestration pen 224, 226, 228 does not extendinto the isolation region 240. Thus, due to the connection region 236, amicro-object (not shown) or other material (not shown) disposed in anisolation region 240 of a sequestration pen 224, 226, 228 can thus beisolated from, and not substantially affected by, a flow of medium 180in the channel 122.

The sequestration pens 224, 226, and 228 of FIGS. 2A-2C each have asingle opening which opens directly to the channel 122. The opening ofthe sequestration pen opens laterally from the channel 122. Theelectrode activation substrate 206 underlays both the channel 122 andthe sequestration pens 224, 226, and 228. The upper surface of theelectrode activation substrate 206 within the enclosure of asequestration pen, forming the floor of the sequestration pen, isdisposed at the same level or substantially the same level of the uppersurface the of electrode activation substrate 206 within the channel 122(or flow region if a channel is not present), forming the floor of theflow channel (or flow region, respectively) of the microfluidic device.The electrode activation substrate 206 may be featureless or may have anirregular or patterned surface that varies from its highest elevation toits lowest depression by less than about 3 microns, 2.5 microns, 2microns, 1.5 microns, 1 micron, 0.9 microns, 0.8 microns, 0.7 microns,0.6 microns, 0.5 microns, 0.4 microns, 0.3 microns, 0.2 microns, 0.1microns, or less. The variation of elevation in the upper surface of thesubstrate across both the channel 122 (or flow region) and sequestrationpens may be less than about 3%, 2%, 1%. 0.9%, 0.8%, 0.5%, 0.3% or 0.1%of the height of the walls of the sequestration pen or walls of themicrofluidic device. While described in detail for the microfluidicdevice 200, this also applies to any of the microfluidic devices 100,230, 250, 280, 290 described herein.

The channel 122 can thus be an example of a swept region, and theisolation regions 240 of the sequestration pens 224, 226, 228 can beexamples of unswept regions. As noted, the channel 122 and sequestrationpens 224, 226, 228 can be configured to contain one or more fluidicmedia 180. In the example shown in FIGS. 2A-2B, the ports 222 areconnected to the channel 122 and allow a fluidic medium 180 to beintroduced into or removed from the microfluidic device 230. Prior tointroduction of the fluidic medium 180, the microfluidic device may beprimed with a gas such as carbon dioxide gas. Once the microfluidicdevice 230 contains the fluidic medium 180, the flow 242 of fluidicmedium 180 in the channel 122 can be selectively generated and stopped.For example, as shown, the ports 222 can be disposed at differentlocations (e.g., opposite ends) of the channel 122, and a flow 242 ofmedium can be created from one port 222 functioning as an inlet toanother port 222 functioning as an outlet.

FIG. 2C illustrates a detailed view of an example of a sequestration pen224 according to the present invention. Examples of micro-objects 246are also shown.

As is known, a flow 242 of fluidic medium 180 in a microfluidic channel122 past a proximal opening 234 of sequestration pen 224 can cause asecondary flow 244 of the medium 180 into and/or out of thesequestration pen 224. To isolate micro-objects 246 in the isolationregion 240 of a sequestration pen 224 from the secondary flow 244, thelength Lcon of the connection region 236 of the sequestration pen 224(i.e., from the proximal opening 234 to the distal opening 238) shouldbe greater than the penetration depth Dp of the secondary flow 244 intothe connection region 236. The penetration depth Dp of the secondaryflow 244 depends upon the velocity of the fluidic medium 180 flowing inthe channel 122 and various parameters relating to the configuration ofthe channel 122 and the proximal opening 234 of the connection region236 to the channel 122. For a given microfluidic device, theconfigurations of the channel 122 and the opening 234 will be fixed,whereas the rate of flow 242 of fluidic medium 180 in the channel 122will be variable. Accordingly, for each sequestration pen 224, a maximalvelocity Vmax for the flow 242 of fluidic medium 180 in channel 122 canbe identified that ensures that the penetration depth Dp of thesecondary flow 244 does not exceed the length Lcon of the connectionregion 236. As long as the rate of the flow 242 of fluidic medium 180 inthe channel 122 does not exceed the maximum velocity Vmax, the resultingsecondary flow 244 can be limited to the channel 122 and the connectionregion 236 and kept out of the isolation region 240. The flow 242 ofmedium 180 in the channel 122 will thus not draw micro-objects 246 outof the isolation region 240. Rather, micro-objects 246 located in theisolation region 240 will stay in the isolation region 240 regardless ofthe flow 242 of fluidic medium 180 in the channel 122.

Moreover, as long as the rate of flow 242 of medium 180 in the channel122 does not exceed Vmax, the flow 242 of fluidic medium 180 in thechannel 122 will not move miscellaneous particles (e.g., microparticlesand/or nanoparticles) from the channel 122 into the isolation region 240of a sequestration pen 224. Having the length Lcon of the connectionregion 236 be greater than the maximum penetration depth Dp of thesecondary flow 244 can thus prevent contamination of one sequestrationpen 224 with miscellaneous particles from the channel 122 or anothersequestration pen (e.g., sequestration pens 226, 228 in FIG. 2D).

Because the channel 122 and the connection regions 236 of thesequestration pens 224, 226, 228 can be affected by the flow 242 ofmedium 180 in the channel 122, the channel 122 and connection regions236 can be deemed swept (or flow) regions of the microfluidic device230. The isolation regions 240 of the sequestration pens 224, 226, 228,on the other hand, can be deemed unswept (or non-flow) regions. Forexample, components (not shown) in a first fluidic medium 180 in thechannel 122 can mix with a second fluidic medium 248 in the isolationregion 240 substantially only by diffusion of components of the firstmedium 180 from the channel 122 through the connection region 236 andinto the second fluidic medium 248 in the isolation region 240.Similarly, components (not shown) of the second medium 248 in theisolation region 240 can mix with the first medium 180 in the channel122 substantially only by diffusion of components of the second medium248 from the isolation region 240 through the connection region 236 andinto the first medium 180 in the channel 122. In some embodiments, theextent of fluidic medium exchange between the isolation region of asequestration pen and the flow region by diffusion is about 90%, 91%,92%, 93%, 94% 95%, 96%, 97%, 98%, 99%, or greater than the amount oftotal fluidic exchange. The first medium 180 can be the same medium or adifferent medium than the second medium 248. Moreover, the first medium180 and the second medium 248 can start out being the same, then becomedifferent (e.g., through conditioning of the second medium 248 by one ormore cells in the isolation region 240, or by changing the medium 180flowing through the channel 122).

The maximum penetration depth Dp of the secondary flow 244 caused by theflow 242 of fluidic medium 180 in the channel 122 can depend on a numberof parameters, as mentioned above. Examples of such parameters include:the shape of the channel 122 (e.g., the channel can direct medium intothe connection region 236, divert medium away from the connection region236, or direct medium in a direction substantially perpendicular to theproximal opening 234 of the connection region 236 to the channel 122); awidth Wch (or cross-sectional area) of the channel 122 at the proximalopening 234; and a width Wcon (or cross-sectional area) of theconnection region 236 at the proximal opening 234; the velocity V of theflow 242 of fluidic medium 180 in the channel 122; the viscosity of thefirst medium 180 and/or the second medium 248, or the like.

In some embodiments, the dimensions of the channel 122 and sequestrationpens 224, 226, 228 can be oriented as follows with respect to the vectorof the flow 242 of fluidic medium 180 in the channel 122: the channelwidth Wch (or cross-sectional area of the channel 122) can besubstantially perpendicular to the flow 242 of medium 180; the widthWcon (or cross-sectional area) of the connection region 236 at opening234 can be substantially parallel to the flow 242 of medium 180 in thechannel 122; and/or the length Lcon of the connection region can besubstantially perpendicular to the flow 242 of medium 180 in the channel122. The foregoing are examples only, and the relative position of thechannel 122 and sequestration pens 224, 226, 228 can be in otherorientations with respect to each other.

As illustrated in FIG. 2C, the width Wcon of the connection region 236can be uniform from the proximal opening 234 to the distal opening 238.The width Wcon of the connection region 236 at the distal opening 238can thus be in any of the ranges identified herein for the width Wcon ofthe connection region 236 at the proximal opening 234. Alternatively,the width Wcon of the connection region 236 at the distal opening 238can be larger than the width Wcon of the connection region 236 at theproximal opening 234.

As illustrated in FIG. 2C, the width Wiso of the isolation region 240 atthe distal opening 238 can be substantially the same as the width Wconof the connection region 236 at the proximal opening 234. The width Wisoof the isolation region 240 at the distal opening 238 can thus be in anyof the ranges identified herein for the width Wcon of the connectionregion 236 at the proximal opening 234. Alternatively, the width Wiso ofthe isolation region 240 at the distal opening 238 can be larger orsmaller than the width Wcon of the connection region 236 at the proximalopening 234. Moreover, the distal opening 238 may be smaller than theproximal opening 234 and the width Wcon of the connection region 236 maybe narrowed between the proximal opening 234 and distal opening 238. Forexample, the connection region 236 may be narrowed between the proximalopening and the distal opening, using a variety of different geometries(e.g. chamfering the connection region, beveling the connection region).Further, any part or subpart of the connection region 236 may benarrowed (e.g. a portion of the connection region adjacent to theproximal opening 234).

FIGS. 2D-2F depict another exemplary embodiment of a microfluidic device250 containing a microfluidic circuit 262 and flow channels 264, whichare variations of the respective microfluidic device 100, circuit 132and channel 134 of FIG. 1. The microfluidic device 250 also has aplurality of sequestration pens 266 that are additional variations ofthe above-described sequestration pens 124, 126, 128, 130, 224, 226 or228. In particular, it should be appreciated that the sequestration pens266 of device 250 shown in FIGS. 2D-2F can replace any of theabove-described sequestration pens 124, 126, 128, 130, 224, 226 or 228in devices 100, 200, 230, 280, 290, or 320. Likewise, the microfluidicdevice 250 is another variant of the microfluidic device 100, and mayalso have the same or a different DEP configuration as theabove-described microfluidic device 100, 200, 230, 280, 290, 320 as wellas any of the other microfluidic system components described herein.

The microfluidic device 250 of FIGS. 2D-2F comprises a support structure(not visible in FIGS. 2D-2F, but can be the same or generally similar tothe support structure 104 of device 100 depicted in FIG. 1A), amicrofluidic circuit structure 256, and a cover (not visible in FIGS.2D-2F, but can be the same or generally similar to the cover 122 ofdevice 100 depicted in FIG. 1A). The microfluidic circuit structure 256includes a frame 252 and microfluidic circuit material 260, which can bethe same as or generally similar to the frame 114 and microfluidiccircuit material 116 of device 100 shown in FIG. 1A. As shown in FIG.2D, the microfluidic circuit 262 defined by the microfluidic circuitmaterial 260 can comprise multiple channels 264 (two are shown but therecan be more) to which multiple sequestration pens 266 are fluidicallyconnected.

Each sequestration pen 266 can comprise an isolation structure 272, anisolation region 270 within the isolation structure 272, and aconnection region 268. From a proximal opening 274 at the channel 264 toa distal opening 276 at the isolation structure 272, the connectionregion 268 fluidically connects the channel 264 to the isolation region270. Generally, in accordance with the above discussion of FIGS. 2B and2C, a flow 278 of a first fluidic medium 254 in a channel 264 can createsecondary flows 282 of the first medium 254 from the channel 264 intoand/or out of the respective connection regions 268 of the sequestrationpens 266.

As illustrated in FIG. 2E, the connection region 268 of eachsequestration pen 266 generally includes the area extending between theproximal opening 274 to a channel 264 and the distal opening 276 to anisolation structure 272. The length Lcon of the connection region 268can be greater than the maximum penetration depth Dp of secondary flow282, in which case the secondary flow 282 will extend into theconnection region 268 without being redirected toward the isolationregion 270 (as shown in FIG. 2D). Alternatively, at illustrated in FIG.2F, the connection region 268 can have a length Lcon that is less thanthe maximum penetration depth Dp, in which case the secondary flow 282will extend through the connection region 268 and be redirected towardthe isolation region 270. In this latter situation, the sum of lengthsLc1 and Lc2 of connection region 268 is greater than the maximumpenetration depth Dp, so that secondary flow 282 will not extend intoisolation region 270. Whether length Lcon of connection region 268 isgreater than the penetration depth Dp, or the sum of lengths Lc1 and Lc2of connection region 268 is greater than the penetration depth Dp, aflow 278 of a first medium 254 in channel 264 that does not exceed amaximum velocity Vmax will produce a secondary flow having a penetrationdepth Dp, and micro-objects (not shown but can be the same or generallysimilar to the micro-objects 246 shown in FIG. 2C) in the isolationregion 270 of a sequestration pen 266 will not be drawn out of theisolation region 270 by a flow 278 of first medium 254 in channel 264.Nor will the flow 278 in channel 264 draw miscellaneous materials (notshown) from channel 264 into the isolation region 270 of a sequestrationpen 266. As such, diffusion is the only mechanism by which components ina first medium 254 in the channel 264 can move from the channel 264 intoa second medium 258 in an isolation region 270 of a sequestration pen266. Likewise, diffusion is the only mechanism by which components in asecond medium 258 in an isolation region 270 of a sequestration pen 266can move from the isolation region 270 to a first medium 254 in thechannel 264. The first medium 254 can be the same medium as the secondmedium 258, or the first medium 254 can be a different medium than thesecond medium 258. Alternatively, the first medium 254 and the secondmedium 258 can start out being the same, then become different, e.g.,through conditioning of the second medium by one or more cells in theisolation region 270, or by changing the medium flowing through thechannel 264.

As illustrated in FIG. 2E, the width Wch of the channels 264 (i.e.,taken transverse to the direction of a fluid medium flow through thechannel indicated by arrows 278 in FIG. 2D) in the channel 264 can besubstantially perpendicular to a width W_(con1) of the proximal opening274 and thus substantially parallel to a width W_(con2) of the distalopening 276. The width W_(con1) of the proximal opening 274 and thewidth W_(con2) of the distal opening 276, however, need not besubstantially perpendicular to each other. For example, an angle betweenan axis (not shown) on which the width W_(con1) of the proximal opening274 is oriented and another axis on which the width W_(con2) of thedistal opening 276 is oriented can be other than perpendicular and thusother than 90°. Examples of alternatively oriented angles include anglesin any of the following ranges: from about 30° to about 90°, from about45° to about 90°, from about 60° to about 90°, or the like.

In various embodiments of sequestration pens (e.g. 124, 126, 128, 130,224, 226, 228, or 266), the isolation region (e.g. 240 or 270) isconfigured to contain a plurality of micro-objects. In otherembodiments, the isolation region can be configured to contain only one,two, three, four, five, or a similar relatively small number ofmicro-objects. Accordingly, the volume of an isolation region can be,for example, at least 5×105, 8×105, 1×106, 2×106, 4×106, 6×106 cubicmicrons, or more.

In various embodiments of sequestration pens, the width W_(ch) of thechannel (e.g., 122) at a proximal opening (e.g. 234) can be within anyof the following ranges: about 50-1000 microns, 50-500 microns, 50-400microns, 50-300 microns, 50-250 microns, 50-200 microns, 50-150 microns,50-100 microns, 70-500 microns, 70-400 microns, 70-300 microns, 70-250microns, 70-200 microns, 70-150 microns, 90-400 microns, 90-300 microns,90-250 microns, 90-200 microns, 90-150 microns, 100-300 microns, 100-250microns, 100-200 microns, 100-150 microns, and 100-120 microns. In someother embodiments, the width W_(ch) of the channel (e.g., 122) at aproximal opening (e.g. 234) can be in a range of about 200-800 microns,200-700 microns, or 200-600 microns. The foregoing are examples only,and the width W_(ch) of the channel 122 can be in other ranges (e.g., arange defined by any of the endpoints listed above). Moreover, theW_(ch) of the channel 122 can be selected to be in any of these rangesin regions of the channel other than at a proximal opening of asequestration pen.

In some embodiments, a sequestration pen has a height of about 30 toabout 200 microns, or about 50 to about 150 microns. In someembodiments, the sequestration pen has a cross-sectional area of about1×10⁴ to about 3×10⁶ square microns, about 2×10⁴ to about 2×10⁶ squaremicrons, about 4×10⁴ to about 1×10⁶ square microns, about 2×10⁴ to about5×10⁵ square microns, about 2×10⁴ to about 1×10⁵ square microns, orabout 2×10⁵ to about 2×10⁶ square microns. In some embodiments, theconnection region has a cross-sectional width of about 20 to about 100microns, about 30 to about 80 microns or about 40 to about 60 microns.

In various embodiments of sequestration pens, the height H_(ch) of thechannel (e.g., 122) at a proximal opening (e.g., 234) can be within anyof the following ranges: 20-100 microns, 20-90 microns, 20-80 microns,20-70 microns, 20-60 microns, 20-50 microns, 30-100 microns, 30-90microns, 30-80 microns, 30-70 microns, 30-60 microns, 30-50 microns,40-100 microns, 40-90 microns, 40-80 microns, 40-70 microns, 40-60microns, or 40-50 microns. The foregoing are examples only, and theheight H_(ch) of the channel (e.g., 122) can be in other ranges (e.g., arange defined by any of the endpoints listed above). The height H_(ch)of the channel 122 can be selected to be in any of these ranges inregions of the channel other than at a proximal opening of asequestration pen.

In various embodiments of sequestration pens a cross-sectional area ofthe channel (e.g., 122) at a proximal opening (e.g., 234) can be withinany of the following ranges: 500-50,000 square microns, 500-40,000square microns, 500-30,000 square microns, 500-25,000 square microns,500-20,000 square microns, 500-15,000 square microns, 500-10,000 squaremicrons, 500-7,500 square microns, 500-5,000 square microns,1,000-25,000 square microns, 1,000-20,000 square microns, 1,000-15,000square microns, 1,000-10,000 square microns, 1,000-7,500 square microns,1,000-5,000 square microns, 2,000-20,000 square microns, 2,000-15,000square microns, 2,000-10,000 square microns, 2,000-7,500 square microns,2,000-6,000 square microns, 3,000-20,000 square microns, 3,000-15,000square microns, 3,000-10,000 square microns, 3,000-7,500 square microns,or 3,000 to 6,000 square microns. The foregoing are examples only, andthe cross-sectional area of the channel (e.g., 122) at a proximalopening (e.g., 234) can be in other ranges (e.g., a range defined by anyof the endpoints listed above).

In various embodiments of sequestration pens, the length L_(con) of theconnection region (e.g., 236) can be in any of the following ranges:about 20 to about 300 microns, about 40 to about 250 microns, about 60to about 200 microns, about 80 to about 150 microns, about 20 to about500 microns, about 40 to about 400 microns, about 60 to about 300microns, about 80 to about 200 microns, or about 100 to about 150microns. The foregoing are examples only, and length Lcon of aconnection region (e.g., 236) can be in a different range than theforegoing examples (e.g., a range defined by any of the endpoints listedabove).

In various embodiments of sequestration pens the width W_(con) of aconnection region (e.g., 236) at a proximal opening (e.g., 234) can bein any of the following ranges: about 20 to about 150 microns, about 20to about 100 microns, about 20 to about 80 microns, about 20 to about 60microns, about 30 to about 150 microns, about 30 to about 100 microns,about 30 to about 80 microns, about 30 to about 60 microns, about 40 toabout 150 microns, about 40 to about 100 microns, about 40 to about 80microns, about 40 to about 60 microns, about 50 to about 150 microns,about 50 to about 100 microns, about 50 to about 80 microns, about 60 toabout 150 microns, about 60 to about 100 microns, about 60 to about 80microns, about 70 to about 150 microns, about 70 to about 100 microns,about 80 to about 150 microns, and about 80 to about 100 microns. Theforegoing are examples only, and the width W_(con) of a connectionregion (e.g., 236) at a proximal opening (e.g., 234) can be differentthan the foregoing examples (e.g., a range defined by any of theendpoints listed above).

In various embodiments of sequestration pens, the width W_(con) of aconnection region (e.g., 236) at a proximal opening (e.g., 234) can beat least as large as the largest dimension of a micro-object (e.g., abiological cell, which may be a immunological cell, such as B cell or aT cell, or a hybridoma cell, or the like) that the sequestration pen isintended for. For example, the width W_(con) of a connection region 236at a proximal opening 234 of a sequestration pen that an immunologicalcell (e.g., B cell) will be placed into can be any of the following:about 20 microns, about 25 microns, about 30 microns, about 35 microns,about 40 microns, about 45 microns, about 50 microns, about 55 microns,about 60 microns, about 65 microns, about 70 microns, about 75 microns,or about 80 microns. The foregoing are examples only, and the widthW_(con) of a connection region (e.g., 236) at a proximal opening (e.g.,234) can be different than the foregoing examples (e.g., a range definedby any of the endpoints listed above).

In various embodiments of sequestration pens, a ratio of the lengthL_(con) of a connection region (e.g., 236) to a width W_(con) of theconnection region (e.g., 236) at the proximal opening 234 can be greaterthan or equal to any of the following ratios: 0.5, 1.0, 1.5, 2.0, 2.5,3.0, 3.5, 4.0, 4.5, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, or more. Theforegoing are examples only, and the ratio of the length L_(con) of aconnection region 236 to a width W_(con) of the connection region 236 atthe proximal opening 234 can be different than the foregoing examples.

In various embodiments of microfluidic devices 100, 200, 230, 250, 280,290, 320 V_(max) can be set around 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8,0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, or 5.0microliters/sec.

In various embodiments of microfluidic devices having sequestrationpens, the volume of an isolation region (e.g., 240) of a sequestrationpen can be, for example, at least 5×10⁵, 8×10⁵, 1×10⁶, 2×10⁶, 4×10⁶,6×10⁶, 8×10⁶, 1×10⁷ cubic microns, or more. In various embodiments ofmicrofluidic devices having sequestration pens, the volume of asequestration pen may be about 5×10⁵, 6×10⁵, 8×10⁵, 1×10⁶, 2×10⁶, 4×10⁶,8×10⁶, 1×10⁷ cubic microns, or more. In some other embodiments, thevolume of a sequestration pen may be about 0.5 nanoliter to about 10nanoliters, about 1.0 nanoliters to about 5.0 nanoliters, about 1.5nanoliters to about 4.0 nanoliters, about 2.0 nanoliters to about 3.0nanoliters, about 2.5 nanoliters, or any range defined by two of theforegoing endpoints.

In various embodiment, the microfluidic device has sequestration pensconfigured as in any of the embodiments discussed herein where themicrofluidic device has about 5 to about 10 sequestration pens, about 10to about 50 sequestration pens, about 100 to about 500 sequestrationpens; about 200 to about 1000 sequestration pens, about 500 to about1500 sequestration pens, about 1000 to about 2000 sequestration pens, orabout 1000 to about 3500 sequestration pens. The sequestration pens neednot all be the same size and may include a variety of configurations(e.g., different widths, different features within the sequestrationpen.

In some other embodiments, the microfluidic device has sequestrationpens configured as in any of the embodiments discussed herein where themicrofluidic device has about 1500 to about 3000 sequestration pens,about 2000 to about 3500 sequestration pens, about 2500 to about 4000sequestration pens about 3000 to about 4500 sequestration pens, about3500 to about 5000 sequestration pens, about 4000 to about 5500sequestration pens, about 4500 to about 6000 sequestration pens, about5000 to about 6500 sequestration pens, about 5500 to about 7000sequestration pens, about 6000 to about 7500 sequestration pens, about6500 to about 8000 sequestration pens, about 7000 to about 8500sequestration pens, about 7500 to about 9000 sequestration pens, about8000 to about 9500 sequestration pens, about 8500 to about 10,000sequestration pens, about 9000 to about 10,500 sequestration pens, about9500 to about 11,000 sequestration pens, about 10,000 to about 11,500sequestration pens, about 10,500 to about 12,000 sequestration pens,about 11,000 to about 12,500 sequestration pens, about 11,500 to about13,000 sequestration pens, about 12,000 to about 13,500 sequestrationpens, about 12,500 to about 14,000 sequestration pens, about 13,000 toabout 14,500 sequestration pens, about 13,500 to about 15,000sequestration pens, about 14,000 to about 15,500 sequestration pens,about 14,500 to about 16,000 sequestration pens, about 15,000 to about16,500 sequestration pens, about 15,500 to about 17,000 sequestrationpens, about 16,000 to about 17,500 sequestration pens, about 16,500 toabout 18,000 sequestration pens, about 17,000 to about 18,500sequestration pens, about 17,500 to about 19,000 sequestration pens,about 18,000 to about 19,500 sequestration pens, about 18,500 to about20,000 sequestration pens, about 19,000 to about 20,500 sequestrationpens, about 19,500 to about 21,000 sequestration pens, or about 20,000to about 21,500 sequestration pens.

Control System Elements. FIGS. 3A through 3B shows various embodimentsof system 150 which can be used to operate and observe microfluidicdevices (e.g. 100, 200, 230, 280, 250, 290, 320) according to thepresent invention. As illustrated in FIG. 3A, the system 150 can includea structure (“nest”) 300 configured to hold a microfluidic device 320,or any other microfluidic device described herein. The nest 300 caninclude a socket 302 capable of interfacing with the microfluidic device320 (e.g., an optically-actuated electrokinetic device 100) andproviding electrical connections from power source 192 to themicrofluidic device 320. The nest 300 can further include an integratedelectrical signal generation subsystem 304. The electrical signalgeneration subsystem 304 can be configured to supply a biasing voltageto socket 302 such that the biasing voltage is applied across a pair ofelectrodes in the microfluidic device 320 when it is being held bysocket 302. Thus, the electrical signal generation subsystem 304 can bepart of power source 192. The ability to apply a biasing voltage tomicrofluidic device 320 does not mean that a biasing voltage will beapplied at all times when the microfluidic device 320 is held by thesocket 302. Rather, in most cases, the biasing voltage will be appliedintermittently, e.g., only as needed to facilitate the generation ofelectrokinetic forces, such as dielectrophoresis or electro-wetting, inthe microfluidic device 320.

As illustrated in FIG. 3A, the nest 300 can include a printed circuitboard assembly (PCBA) 322. The electrical signal generation subsystem304 can be mounted on and electrically integrated into the PCBA 322. Theexemplary support includes socket 302 mounted on PCBA 322, as well.

Typically, the electrical signal generation subsystem 304 will include awaveform generator (not shown). The electrical signal generationsubsystem 304 can further include an oscilloscope (not shown) and/or awaveform amplification circuit (not shown) configured to amplify awaveform received from the waveform generator. The oscilloscope, ifpresent, can be configured to measure the waveform supplied to themicrofluidic device 320 held by the socket 302. In certain embodiments,the oscilloscope measures the waveform at a location proximal to themicrofluidic device 320 (and distal to the waveform generator), thusensuring greater accuracy in measuring the waveform actually applied tothe device. Data obtained from the oscilloscope measurement can be, forexample, provided as feedback to the waveform generator, and thewaveform generator can be configured to adjust its output based on suchfeedback. An example of a suitable combined waveform generator andoscilloscope is the Red Pitaya™.

In certain embodiments, the nest 300 further comprises a controller 308,such as a microprocessor used to sense and/or control the electricalsignal generation subsystem 304. Examples of suitable microprocessorsinclude the Arduino™ microprocessors, such as the Arduino Nano™. Thecontroller 308 may be used to perform functions and analysis or maycommunicate with an external master controller 154 (shown in FIG. 1A) toperform functions and analysis. In the embodiment illustrated in FIG. 3Athe controller 308 communicates with a master controller 154 through aninterface 310 (e.g., a plug or connector).

In some embodiments, the nest 300 can comprise an electrical signalgeneration subsystem 304 comprising a Red Pitaya™ waveformgenerator/oscilloscope unit (“Red Pitaya unit”) and a waveformamplification circuit that amplifies the waveform generated by the RedPitaya unit and passes the amplified voltage to the microfluidic device100. In some embodiments, the Red Pitaya unit is configured to measurethe amplified voltage at the microfluidic device 320 and then adjust itsown output voltage as needed such that the measured voltage at themicrofluidic device 320 is the desired value. In some embodiments, thewaveform amplification circuit can have a +6.5V to −6.5V power supplygenerated by a pair of DC-DC converters mounted on the PCBA 322,resulting in a signal of up to 13 Vpp at the microfluidic device 100.

As illustrated in FIG. 3A, the support structure 300 can further includea thermal control subsystem 306. The thermal control subsystem 306 canbe configured to regulate the temperature of microfluidic device 320held by the support structure 300. For example, the thermal controlsubsystem 306 can include a Peltier thermoelectric device (not shown)and a cooling unit (not shown). The Peltier thermoelectric device canhave a first surface configured to interface with at least one surfaceof the microfluidic device 320. The cooling unit can be, for example, acooling block (not shown), such as a liquid-cooled aluminum block. Asecond surface of the Peltier thermoelectric device (e.g., a surfaceopposite the first surface) can be configured to interface with asurface of such a cooling block. The cooling block can be connected to afluidic path 314 configured to circulate cooled fluid through thecooling block. In the embodiment illustrated in FIG. 3A, the supportstructure 300 comprises an inlet 316 and an outlet 318 to receive cooledfluid from an external reservoir (not shown), introduce the cooled fluidinto the fluidic path 314 and through the cooling block, and then returnthe cooled fluid to the external reservoir. In some embodiments, thePeltier thermoelectric device, the cooling unit, and/or the fluidic path314 can be mounted on a casing 312 of the support structure 300. In someembodiments, the thermal control subsystem 306 is configured to regulatethe temperature of the Peltier thermoelectric device so as to achieve atarget temperature for the microfluidic device 320. Temperatureregulation of the Peltier thermoelectric device can be achieved, forexample, by a thermoelectric power supply, such as a Pololu™thermoelectric power supply (Pololu Robotics and Electronics Corp.). Thethermal control subsystem 306 can include a feedback circuit, such as atemperature value provided by an analog circuit. Alternatively, thefeedback circuit can be provided by a digital circuit.

In some embodiments, the nest 300 can include a thermal controlsubsystem 306 with a feedback circuit that is an analog voltage dividercircuit (not shown) which includes a resistor (e.g., with resistance 1kOhm+/−0.1%, temperature coefficient+/−0.02 ppm/C0) and a NTC thermistor(e.g., with nominal resistance 1 kOhm+/−0.01%). In some instances, thethermal control subsystem 306 measures the voltage from the feedbackcircuit and then uses the calculated temperature value as input to anon-board PID control loop algorithm. Output from the PID control loopalgorithm can drive, for example, both a directional and apulse-width-modulated signal pin on a Pololu™ motor drive (not shown) toactuate the thermoelectric power supply, thereby controlling the Peltierthermoelectric device.

The nest 300 can include a serial port 324 which allows themicroprocessor of the controller 308 to communicate with an externalmaster controller 154 via the interface 310 (not shown). In addition,the microprocessor of the controller 308 can communicate (e.g., via aPlink tool (not shown)) with the electrical signal generation subsystem304 and thermal control subsystem 306. Thus, via the combination of thecontroller 308, the interface 310, and the serial port 324, theelectrical signal generation subsystem 304 and the thermal controlsubsystem 306 can communicate with the external master controller 154.In this manner, the master controller 154 can, among other things,assist the electrical signal generation subsystem 304 by performingscaling calculations for output voltage adjustments. A Graphical UserInterface (GUI) (not shown) provided via a display device 170 coupled tothe external master controller 154, can be configured to plottemperature and waveform data obtained from the thermal controlsubsystem 306 and the electrical signal generation subsystem 304,respectively. Alternatively, or in addition, the GUI can allow forupdates to the controller 308, the thermal control subsystem 306, andthe electrical signal generation subsystem 304.

FIG. 3B is an optical schematic of an optical apparatus 350 of thesystem 150 for a microfluidic device. In some embodiments, the opticalapparatus 350 can comprise a structured light modulator 330. Thestructured light modulator 330 can include a digital mirror device (DMD)or a microshutter array system (MSA), either of which can be configuredto receive light from a light source 332 and transmits a subset of thereceived light into the optical apparatus 350. Alternatively, thestructured light modulator 330 can include a device that produces itsown light (and thus dispenses with the need for a light source 332),such as an organic light emitting diode display (OLED), a liquid crystalon silicon (LCOS) device, a ferroelectric liquid crystal on silicondevice (FLCOS), or a transmissive liquid crystal display (LCD). Thestructured light modulator 330 can be, for example, a projector. Thus,the structured light modulator 330 can be capable of emitting bothstructured and unstructured light. In certain embodiments, an imagingmodule and/or motive module of the system can control the structuredlight modulator 330.

In some embodiments, the optical apparatus 350 can have a microscopeconfiguration. In such embodiments, the nest 300 and the structuredlight modulator 330 can be individually configured to be integrated intothe microscope configuration of the optical apparatus 350. In someembodiments, the optical apparatus 350 can further include one or moreimage sensors or detectors 348. In some embodiments, the image sensor348 is controlled by an imaging module. The image senor 348 can includean eye piece, a charge-coupled device (CCD), a camera (e.g., a digitalcamera), or any combination thereof. If at least two image sensors 348are present, one image senor can be, for example, a fast-frame-ratecamera while the other detector can be a high sensitivity camera.Furthermore, the optical apparatus 350 can be configured to receivereflected and/or emitted light from a microfluidic device 320 and focusat least a portion of the reflected and/or emitted light on the one orimage sensors 348.

In some embodiments, the optical apparatus 350 is configured to use atleast two light sources. For example, a first light source 332 can beused to produce structured light (e.g., via the light modulatingsubsystem 330) and a second light source 334 can be used to provideunstructured light. The first light source 332 can produce structuredlight for optically-actuated electrokinesis and/or fluorescentexcitation, and the second light source 334 can be used to providebright field illumination. In these embodiments, the motive module 164can be used to control the first light source 332 and the imaging module164 can be used to control the second light source 334. The opticalapparatus 350 can be configured to receive structured light from thestructured light modulator 330 and project the structured light on atleast a first region in a microfluidic device, such as anoptically-actuated electrokinetic device, when the device is being heldby the nest 300, and receive reflected and/or emitted light from themicrofluidic device and image at least a portion of such reflectedand/or emitted light onto the image senor 348. The optical apparatus 350can be further configured to receive unstructured light from a secondlight source and project the unstructured light on at least a secondregion of the microfluidic device, when the device is held by the nest300. In certain embodiments, the first and second regions of themicrofluidic device 320 can be overlapping regions. For example, thefirst region can be a subset of the second region.

In FIG. 3B, the first light source 332 is shown supplying light to astructured light modulator light 330, which provides structured light tothe microfluidic device 320. The second light source 334 is shownproviding unstructured light via a beam splitter 336. Structured lightfrom the light modulator 330 and unstructured light from the secondlight source 334 travel from the beam splitter 336 together to reach asecond beam splitter (or dichroic filter 338, depending on the lightprovided by the light modulator 330), where the light gets reflecteddown through the objective 340 to the microfluidic device 320. Reflectedand/or emitted light from the microfluidic device 320 then travels backup through the objective 340, through the beam splitter and/or dichroicfilter 338, and to a dichroic filter 346. Only a fraction of the lightreaching dichroic filter 346 passes through and reaches the detector348.

In some embodiments, the second light source 334 emits blue light. Withan appropriate dichroic filter 346, blue light reflected from themicrofluidic device 320 is able to pass through dichroic filter 346 andreach the detector 348. In contrast, structured light coming from thelight modulator 330 gets reflected from the microfluidic device 320, butdoes not pass through the dichroic filter 346. In this example, thedichroic filter 346 is filtering out visible light having a wavelengthlonger than 495 nm. Such filtering out of the light from the lightmodulator 330 would only be complete (as shown) if the light emittedfrom the light modulator did not include any wavelengths shorter than495 nm. In practice, if the light coming from the light modulator 330includes wavelengths shorter than 495 nm (e.g., blue wavelengths), thensome of the light from the light modulator would pass through filter 346to reach the image senor 348. In such an embodiment, the filter 346 actsto change the balance between the amount of light that reaches the imagesenor 348 from the first light source 332 and the second light source334. This can be beneficial if the first light source 332 issignificantly stronger than the second light source 334. In otherembodiments, the second light source 334 can emit red light, and thedichroic filter 346 can filter out visible light other than red light(e.g., visible light having a wavelength shorter than 650 nm).

In certain embodiments, the first light source 332 can emit a broadspectrum of wavelengths (e.g., “white” light). The first light source332 can emit, for example, at least one wavelength suitable forexcitation of a fluorophore. The first light source 332 can besufficiently powerful such that structured light emitted by the lightmodulator 330 is capable of activating light actuated electrophoresis ina light-actuated actuated microfluidic device 320. In certainembodiments, the first light source 332 can include a high intensitydischarge arc lamp, such as those Including metal halides, ceramicdischarge, sodium, mercury, and/or xenon. In other embodiments, thefirst light source 332 can include one or more LEDs (e.g., an army ofLEDs, such as a 2×2 array of 4 LEDs or a 3×3 array of 9 LEDs). TheLED(s) can include a broad-spectrum “white” light LED (e.g., theUHP-T-LED-White by PRIZMATIX), or various narrowband wavelength LEDs(e.g., emitting a wavelength of about 380 nm, 480 nm, or 560 nm). Instill other embodiments, the first light source 332 can incorporate alaser configured to emit light at selectable wavelengths (e.g., for OETand/or fluorescence).

In certain embodiments, the second light source 334 is suitable forbright field illumination. Thus, the second light source 334 can includeone or more LEDs (e.g., an array of LEDs, such as a 2×2 array of 4 LEDsor a 3×3 array of 9 LEDs). The LED(s) can be configured to emit white(i.e., wide spectrum) light, blue light, red light, etc. In someembodiments, the second light source 334 can emit light having awavelength of 495 nm or shorter. For example, the second light source622 can emit light having a wavelength of substantially 480 nm,substantially 450 nm, or substantially 380 nm. In other embodiments, thesecond light source 334 can emit light having a wavelength of 650 nm orlonger. For example, the second light source 334 can emit light having awavelength of substantially 750 nm. In still other embodiments, thesecond light source 334 can emit light having a wavelength ofsubstantially 560 nm.

In certain embodiments, the optical apparatus 350 include a dichroicfilter 346 that filters out, at least partially, visible light having awavelength longer than 495 nm. In other embodiments, the opticalapparatus 350 include a dichroic filter 346 that filters out, at leastpartially, visible light having a wavelength shorter than 650 nm (orshorter than 620 nm). More generally, the optical apparatus 350 can alsoinclude a dichroic filter 346 configured to reduce or substantiallyprevent structured light from a first light source 332 from reaching adetector 348. Such a filter 346 can be located proximal to the detector346 (along the optical apparatus). Alternatively, the optical apparatus350 can include one or more dichroic filters 346 that is/are configuredto balance the amount of structure light (e.g., visible structuredlight) from the light modulator 330 and the amount of unstructured light(e.g., visible unstructured light) from the second light source 334 thatreaches said detector 348. Such balance can be used to ensure that thestructured light does not overwhelm the unstructured light at thedetector 348 (or in images obtained by the detector 348).

In some embodiments, the optical apparatus 350 can further include atleast one tube lens 381 located between the objective lens 340 and theimage sensor 348 in an imaging path of the apparatus 350. The objectivelens 340 no longer projects an intermediate image directly into anintermediate image plane. Instead, the objective lens 340 is configuredso that light emerging from a rear aperture of the objective lens 340 isfocused to infinity, and the tube lens 381 is configured to form animage at a focal plane of the tube lens 381. Light beams exiting theinfinity-focused objective lens 340 are collimated, such that thebeam-splitter 338, the filter 346 polarizers, and other componentsrequiring a parallel beam can be easily introduced into the imagingpath. After passing through these auxiliary optical devices, theparallel light beams can be configured to converge and form an image ofthe microfluidic device 320 by the tube lens 381. Without the tube lens381, insertion of the beam-splitter and other components in the imagingpath can introduce spherical aberration and possibly “ghost images”effect as a result of converging light beams passing through thebeam-splitter. The objective lens 340 and the tube lens 381 together canproduce an image at the image senor 348. The region between theobjective lens 340 and the tube lens 381 (infinity space) provides apath of parallel light beams into which complex optical components canbe placed without the introduction of spherical aberration ormodification of the objective lens 340 working distance.

FIG. 4A is an optical schematic of a system 1000 for imaging andmanipulating micro-objects. The system 1000 can comprise a microfluidicdevice 1320, such as a light-actuated microfluidic (or “LAMF”) device,and an optical apparatus 1350. The microfluidic device 1320 can be anymicrofluidic device described herein or otherwise known in the art. Forexample, the microfluidic device can comprise an enclosure configured tohold one or more micro-objects in a fluidic medium, and a substrate 1320c. FIG. 4B provides an image of portion (or a field of view) or anexemplary a microfluidic device 1320. The substrate 1320 c of the LAMFdevice can comprise a surface 1120 and a plurality of dielectrophoresis(DEP) electrodes on (or comprised by or integrated with) the surface.The microfluidic device 1320 can further comprise a flow region 1122 andone or more (e.g., a plurality of) sequestration pens 1226. Asillustrated in FIG. 4B, each sequestration pen 1226 can be fluidicallyconnected to the flow region 1122. The flow region 1122 and theplurality of sequestration pens 1226 can be disposed on the surface 1120of the substrate of the microfluidic device 1320. The microfluidicdevice 1320 can further comprise a cover 1320 a. The cover 1320 a cancomprise a ground electrode. As illustrated in FIG. 4B, the cover 1320 acan be transparent to visible light.

The optical apparatus 1350 can be configured to perform imaging,analysis and manipulation of one or more micro-objects within theenclosure of the microfluidic device 1320. As shown in FIG. 4A, theoptical apparatus 1350 can comprise a structured light modulator 1330, afirst tube lens 1381, an objective lens 1340, a dichroic beam splitter1338, a second tube lens 1382, and an image sensor 1348. The opticalapparatus 1350 can further comprise a first light source 1332.

In general, the structured light modulator 1330 can be configured toreceive unstructured light beams from the first light source 1332 andtransmit structured light beams to the first tube lens 1381. Asdiscussed in greater detail above, the structured light beams can beused to selectively activate one or more of the plurality ofdielectrophoresis (DEP) electrodes on the surface 1120. The first tubelens 1381 is configured to capture the structured light beams from thestructured light modulator 1330. The objective lens 1340 is configuredto image at least a portion of the plurality of sequestration pens 1226of the microfluidic device 1320 within a field of view. The field ofview, for example, can be larger than 10 mm×10 mm, 11 mm×11 mm, 12 mm×12mm, 13 mm×13 mm, 14 mm×14 mm, 15 mm×15 mm, etc.

The dichroic beam splitter 1338 is configured to reflect or transmitlight beams from the first tube lens 1381 to the objective lens 1340,and to transmit or reflect light beams received from the objective lens1340 to the second tube lens 1382. The second tube lens 1382 isconfigured to receive the light beams from the dichroic beam splitter1338 and to transmit the light beams to an image sensor 1348. The imagesensor 1348 is configured to receive light beams from the second tubelens and generate therefrom an image of at least a portion of theplurality of sequestration pens 1226 within the field of view.

In some embodiments, the structured light modulator 1330 can include adigital mirror device (DMD) or a microshutter array system (MSA), eitherof which can be configured to receive light from a light source 332 andselectively transmits a subset of the received light. One exemplary DMDthat is suitable for the any of the optical apparatus disclosed herein,including optical apparatus 1350, is the DLP-9000 (Texas Instruments).Alternatively, the structured light modulator 1330 can include a devicethat produces its own light (and thus dispenses with the need for alight source 1332), such as an organic light emitting diode display(OLED), a liquid crystal on silicon (LCOS) device, a ferroelectricliquid crystal on silicon device (FLCOS), or a transmissive liquidcrystal display (LCD). The structured light modulator 1330 can be, forexample, a projector. Thus, the structured light modulator 1330 can becapable of emitting both structured and unstructured light.

In some embodiments, the structured light modulator 1330 can beconfigured to modulate light beams received from the first light source1332 and transmits a plurality of illumination light beams, which arestructured light beams. The structured light beams can comprise theplurality of illumination light beams. The plurality of illuminationlight beams can be selectively activated to generate a plurality ofilluminations patterns. In some embodiments, the structured lightmodulator 1330 can be configured to generate an illumination pattern,which can be moved and adjusted. The optical apparatus 1350 can furthercomprise a control unit (not shown) which is configured to adjust theillumination pattern to selectively activate the one or more of theplurality of DEP electrodes and generate DEP forces to move the one ormore micro-objects inside the plurality of sequestration pens 1226.

For example, the plurality of illuminations patterns can be adjustedover time in a controlled manner to manipulate the micro-objects in themicrofluidic device 1320. For example, each of the plurality ofillumination patterns can be shifted to shift the location of the DEPforce generated and to move the structured light for one position toanother in order to move the micro-objects within the enclosure of themicrofluidic apparatus 1320.

Referring to FIG. 4A, in some embodiments, the optical apparatus 1350 isconfigured such that each of the plurality of sequestration pens 1226within the field of view is simultaneously in focus at the image sensor1348 and at the structured light modulator 1330. For example, theoptical apparatus 1350 can have a confocal configuration or confocalproperty. The optical apparatus 1350 can be further configured such thatonly each interior area of the flow region and/or each of the pluralityof sequestration pens 1226 within the field of view is imaged onto theimage sensor 1348 in order to reduce overall noise to increase thecontrast and resolution of the image.

For example, the structured light modulator 1330 can be disposed at aconjugate plane of the image sensor 1348. The structured light modulator1330 can receive unstructured light beams from the first light source1332 and modulate the light beams to generate a plurality ofillumination beams, which are structured light beams. The active area ofthe structured light modulator can be at least 10 mm×10 mm (e.g., atleast 10.5 mm×10.5 mm, 11 mm×11 mm, 11.5 mm×11.5 mm, 12 mm×12 mm, 12.5mm×12.5 mm, 13 mm×13 mm, 13.5 mm×13.5 mm, 14 mm×14 mm, 14.5 mm×14.5 mm,15 mm×15 mm, or greater). The first tube lens 1381 can have a largeclear aperture, for example, a diameter larger than 40 mm, 41 mm, 42 mm,43 mm, 44 mm, 45 mm, 46 mm, 47 mm, 48 mm, 49 mm, 50 mm, etc. Thus, thefirst tube lens 1381 can have an aperture that is large enough tocapture all (or substantially all) of the light beams emanating from thestructured light modulator.

FIG. 4C illustrates the first tube lens 1381 of the optical apparatus1350 in FIG. 4A is configured to capture all light beams from thestructured light modulator 1330. The structured light modulator 1330 canhave a plurality of mirrors. Each mirror of the plurality of mirrors canhave a size of 5 microns×5 microns, 6 microns×6 microns, 7 microns×7microns, 8 microns×8 microns, 9 microns×9 microns, 10 microns×10microns, or any values therebetween. The structured light modulator 1330can include an array of mirrors (or pixels) that is 2000×1000,2580×1600, 3000×2000, or any values therebetween. For a mirror size of7.6 microns×7.6 microns, the structured light modulator 1330 can havethe dimensions of 15.2 mm×7.6 mm, 19.6 mm×12.2 mm, 22.8 mm×15.2 mm, orany values therebetween. As shown in FIG. 4C, in some embodiments, onlya portion of an illumination area 1330 a of the structured lightmodulator 1330 is used. For example, 50%, 60%, 80% or any valuestherebetween of the illumination area 1330 a of the structured lightmodulator 1330 is used. The first tube lens 1381 can be configured tohave a large field of view 1381 a that is larger than the illuminationarea 1330 a of the structured light modulator 1330. The first tube lens1381 can be configured to capture all light beams from the structuredlight modulator 1330.

Referring to FIG. 4A, in some embodiments, the first tube lens 1381 canbe configured to generate collimated light beams and transmit thecollimated light beams to the objective lens 1340. The objective 1340can receive the collimated light beams from the first tube lens 1381 andfocus the collimated light beams into each interior area of the flowregion and each of the plurality of sequestration pens 1226 within thefield of view of the image sensor 1348 or the optical apparatus 1350. Insome embodiments, the first tube lens 1381 can be configured to generatea plurality of collimated light beams and transmit the plurality ofcollimated light beams to the objective lens 1340. The objective 1340can receive the plurality of collimated light beams from the first tubelens 1381 and converge the plurality of collimated light beams into eachof the plurality of sequestration pens 1226 within the field of view ofthe image sensor 1348 or the optical apparatus 1350.

In some embodiments, the optical apparatus 1350 can be configured toilluminate the at least a portion of sequestration pens with a pluralityof illumination spots. The objective 1340 can receive the plurality ofcollimated light beams from the first tube lens 1381 and project theplurality of illumination spots into each of the plurality ofsequestration pens 1226 within the field of view. For example, each ofthe plurality of illumination spots can have a size of about 10microns×30 microns, 30 microns×60 microns, 60 microns×120 microns, 80microns×100 microns, 100 microns×140 microns and any values therebetween. For example, each of the plurality of illumination spots can anarea of about 4000 to about 10000, 5000 to about 15000, 7000 to about20000, 8000 to about 22000, 10000 to about 25000 square microns and anyvalues there between.

In some embodiments, the optical apparatus 1350 can be configured toperform confocal imaging. For example, the structured light modulator1330 can be configured to generate a thin strip that can scan throughthe plurality of sequestration pens 1226 within the field of view toreduce out-of-focus light to reduce overall noise. For another example,the structured light modulator 1330 can be configured to generate aplurality of illuminations spots within diffraction limits. For anotherexample, the structured light modulator 1330 can be configured to movealong an optical axis pf the optical apparatus 1350 to obtain aplurality of images along the optical axis, the plurality of imagesalong the optical axis can be combined to reconstruct 3 dimensionalimages of the micro-objects in the plurality of sequestration pens 1226in the microfluidic apparatus 1320.

The second tube lens 1382 is located between the objective lens 1340 andthe image sensor 1348 in an imaging path of the apparatus 1350. Theobjective lens 1340 is configured so that light emerging from a rearaperture of the objective lens 1340 is focused to infinity, and thesecond tube lens 1382 is configured to form an image of themicro-objects in the plurality of sequestration pens 1226 at a focalplane of the tube lens 1382. Light beams exiting the infinity-focusedobjective lens 1340 can be configured to be collimated, such that thebeam-splitter 1338 and other components can be easily introduced intothe imaging path of the optical apparatus 1350 without the introductionof spherical aberration or modification of a working distance of theobjective lens 1340.

In some embodiments, the optical apparatus 1350 can further comprise anest 1300. The nest 1300 can be configured to hold the microfluidicdevice 1320 and provide electrical connection to the enclosure. The nest1300 can be integrated with the optical apparatus 1350 and be a part ofthe apparatus 1350. The nest 1300 can be further configured to providefluidic connections to the enclosure. Users can just load themicrofluidic apparatus 1320 into the nest 1300. In some otherembodiments, the nest 1300 can be a separate component independent ofthe optical apparatus 1350.

FIG. 5A illustrates a plurality of light sources can be used in anoptical apparatus 5350 and a light-actuated micro-fluidic apparatus insome other embodiments. As discussed above, a variety of light sourcesmay be used as the first light source 5332, providing structured lightto the DMD tube lens 5460. In some embodiments, the first light source5332 may be a light emitting diode (LED). The light source 5332 may emitlight 505 having a broad spectrum of light wavelengths, which uponimpinging a DMD 5440, provides structured light 515 to a DMD foldingmirror 5336, which may be a dichroic folding mirror. DMD folding mirror5336 redirects structured light 515 to the DMD tube lens 5460. In someembodiments, the optical apparatus can further comprise a second lightsource 5334 configured to provide unstructured bright field illumination525 through DMD folding mirror 5336 to arrive at DMD tube lens 5460. Insome other embodiments, the optical apparatus can further comprise athird light source 5335, for example, a laser light source, providinglight illumination 535, which may be configured to heat up the pluralityof sequestration pens in the microfluidic apparatus. FIG. 5B illustratesan example of light transmission through the dichroic folding mirror5336, as configured for the plurality of light sources in FIG. 5A.

Structured light 515, arriving from the DMD 5440, may have a wavelengthfrom about 400 nm to about 710 nm, and may be used, after passingthrough the DMD tube lens 5460 to any microfluidic device as describedherein for photoactivation of a DEP or OEW configuration within themicrofluidic device. The structured light 515, having a wavelength ofabout 400 nm to about 710 nm, may alternatively or in addition, providefluorescent excitation illumination to the microfluidic device. In someembodiments, the structured light 515 may have a wavelength of about 400nm to about 650 nm, about 400 nm to about 600 nm, about 400 nm to about550 nm, about 400 nm to about 500 nm, about 450 nm to about 710 nm,about 450 to about 600 nm, or about 450 nm to about 550 nm.

Unstructured brightfield illumination 525 arrives from the second lightsource 5334 to the DMD folding mirror 5336 and may pass through mirror5336 substantially (e.g., within about 10%) at the same wavelengthand/or substantially (e.g., within about 10%) at the same intensitybefore impinging on the mirror. Alternatively, the mirror 5336 may foldto permit brightfield illumination 525 to pass, enter tube lens 5460 andtravel further to enter the microfluidic device, which may be anymicrofluidic device as described herein. The brightfield illuminationlight 525 may have any suitable wavelength, and in some embodiments, mayhave a wavelength of about 400 nm to about 760 nm. In some embodiments,the brightfield illumination light 525 may have a wavelength of morethan about 5336 nm and less than about 760 nm, more than about 600 nmand less than about 750 nm, or about 650 nm and less than about 750 nm.In some embodiments, the brightfield illumination light may have awavelength of about 700 nm, about 710 nm, about 720 nm, about 730 nm,about 740 nm, or about 750 nm.

The third illumination light 535 may pass through DMD mirror 5336 or DMDmirror 5336 may fold to permit illumination light 535 to pass and entertube lens 5460, and travel further to the microfluidic device, which maybe any microfluidic device as described herein. The third illuminationlight 535, which may be a laser, may be configured to heat portions ofone or more sequestration pens within the microfluidic device. The laserillumination 535 may be configured to heat fluidic medium, amicro-object, a wall or a portion of a wall of a sequestration pen, ametal target disposed within a microfluidic channel or sequestration penof the microfluidic channel, or a photoreversible physical barrierwithin the microfluidic device. In other embodiments, the laserillumination 535 may be configured to initiate photocleavage of surfacemodifying moieties of a modified surface of the microfluidic device orphotocleavage of moieties providing adherent functionalities formicro-objects within a sequestration pen within the microfluidic device.The laser illumination 535 may have any suitable wavelength. In someembodiments, the laser illumination 535 may have a wavelength of about350 nm to about 900 nm, about 370 nm to about 850 nm, about 390 nm toabout 825 nm, about 400 nm to about 800 nm, about 450 nm to about 750nm, or any value therebetween. In some embodiments, the laserillumination 535 may have a wavelength of about 700 nm, about 710 nm,about 720 nm, about 730 nm, about 740 nm, about 750 nm, about 760 nm,about 770 nm, about 780 nm, about 790 nm, about 800 nm, about 810 nm ormore.

FIG. 5C is a schematic of a system 5000 including an optical apparatus5350 that includes a first light source 5335, a second light source5334, and a third light source 5332. The first light source 5335 cantransmit light to a structured light modulator 5330, which can include adigital mirror device (DMD) or a microshutter array system (MSA), eitherof which can be configured to receive light from the first light source5335 and selectively transmit a subset of the received light into theoptical apparatus 5350. Alternatively, the structured light modulator5330 can include a device that produces its own light (and thusdispenses with the need for a light source 5335), such as an organiclight emitting diode display (OLED), a liquid crystal on silicon (LCOS)device, a ferroelectric liquid crystal on silicon device (FLCOS), or atransmissive liquid crystal display (LCD). The structured lightmodulator 5330 can be, for example, a projector. Thus, the structuredlight modulator 5330 can be capable of emitting both structured andunstructured light. In certain embodiments, an imaging module and/ormotive module of the system can control the structured light modulator5330. The structured light modulator 5330 can transmit a subset of lightto a first dichroic beam splitter 5338, which can reflect this light toa first tube lens 5381.

The second light source 5334 can transmit light to a second dichroicbeam splitter 5336, which also receives light from the third lightsource 5332. The third light source 5332 can transmit light through amatched pair relay lens 5001 to a mirror 5003. In addition, the beamsplitter 5338 can receive and transmit light from the third light source5332 and second light source 5334 to the first tube lens 5381. The lightfrom the first, second, and third light sources passes through the firsttube lens 5381 and is transmitted to a third dichroic beam splitter 5339and filter changer 5005. The third dichroic beam splitter can reflect aportion of the light and transmit the light through one or more filtersin the filter changer 5005 and to the objective 5340, which may be anobjective changer with a plurality of different objectives that can beswitched on demand. Some of the light may pass through the thirddichroic beam splitter 5339 and be terminated or absorbed by a beamblock 5007. The light reflected from the third dichroic beam splitter5339 passes through the objective 5340 to illuminate the sample plane5320, which can be a portion of a microfluidic device such as thesequestration pens described herein. The combined light can function toilluminate, heat, and/or excite the samples in the sample plane 5320.Light can be reflected off and/or emitted from the sample plane 5320 topass back through the objective changer 5340, through the filter changer5005, and through the third dichroic beam splitter 5339 to a second tubelens 5382. The light can pass through the second tube lens 5382 (orimaging tube lens 5382) and be reflected from a mirror 5015 to animaging sensor 5348. Stray light baffles 5009, 5011, and 5013 can beplaced between the first tube lens 5381 and the third dichroic beamsplitter 5339, between the third dichroic beam splitter 5339 and thesecond tube lens 5382, and between the second tube lens 5382 and theimaging sensor 5348.

FIG. 6A is a schematic of a system 2000 including an optical apparatus2350 with an excitation filter 2346 a and an emission filter 2346 baccording to some other embodiments of the disclosure. Excitationfilters and emission filters can be inserted into the optical paths ofthe optical apparatus 2350. The first tube lens 2381, the second tubelens 2382 and the objective lens 2340 form infinity-corrected opticalconfiguration such that the beam-splitter 2338, the excitation filter2346 a and the emission filter 2346 b can be easily introduced into theoptical path of the optical apparatus 2350 without the introduction ofspherical aberration.

FIG. 6B is a schematic of a system 3000 including an optical apparatus3350 where a beam splitter 3338 is configured to reflect light beamsfrom a first light source 3332 according to some other embodiments ofthe disclosure. The beam splitter can be configured to transmit orreflect light beams from the first light source, and reflect or transmitlight beams from the objective lens, as shown in FIG. 4A and FIG. 6Brespectively.

Referring back to FIG. 4A, the optical apparatus can comprise theobjective lens 1340 that is specifically designed and configured forviewing and manipulating of micro-objects in the microfluidic device1320. For example, conventional microscope objective lenses are designedto view micro-objects on a slide or through 5 mm of aqueous fluid, whilemicro-objects in the microfluidic device 1320 are inside the pluralityof sequestration pens 1226 which have a depth of 20, 30, 40, 50, 60 70,80 microns or any values therebetween. In some embodiments, atransparent cover 1320 a, for example, glass or ITO cover with athickness of about 750 microns, can be placed on top of the plurality ofsequestration pens 1226. Thus, the images of the micro-objects obtainedby using the conventional microscope objective lenses may have largeaberrations such as spherical and chromatic aberrations, which candegrade the quality of the images. The objective lens 1340 of theoptical apparatus 1350 can be configured to correct the spherical andchromatic aberrations in the optical apparatus 1350.

FIG. 6C is a schematic of a system 4000 including an optical apparatus4350 with a correction lens 4340 b to compensate aberration from anobjective lens 4340 according to yet some other embodiments of thedisclosure. The objective lens 4340 can be a conventional microscopeobjective lens, for example, an objective lens with a magnification, 4×,10×, 20×, etc. from Olympus or Nikon. It can be very challenging andcostly to redesign the microscope objective lens because of thecomplexity of the optical design. In some embodiments, the correctionlens 4340 b can be used to compensate, correct and minimize the residualaberrations resulted from using a conventional microscope objective lens4340. For example, the correction lens 4340 b can be inserted betweenthe objective lens 4340 and the beam splitter 1338. For another example,the correction lens can be inserted between the objective lens and themicrofluidic device. In some other embodiments, the first tube lens andthe second tube lens can be configured to minimize the residualaberrations of the conventional microscope objective lens.

Again, referring back to FIG. 4A, the optical apparatus 1350 of thesystem 1000 for imaging and manipulating micro-objects often havemechanical constraint because of the limited available space. The tubelenses 1381, 1382 for the optical apparatus 1350 have to be specificallydesigned and configured to meet the mechanical and optical requirements.In some embodiments, the first tube lens can have a focal length ofabout 155 mm or about 162 mm and the second tube lens can have a focallength of about 180 mm. In some other embodiments, the first tube lenscan have a focal length of about 180 mm and the second tube lens canhave a focal length of about 200 mm.

The conjugates of a front focal point and a back focal point of the tubelenses 1381, 1382 of the optical apparatus 1350 are located differentlythan those of a conventional tube lens. In general, for a conventionaltube lens, a “Back Focal Length (BFL)” and “Front Focal Length (FFL)”are about equal. The conjugates of a front focal point and a back focalpoint of the conventional tube lens are normally equally spaced from amidpoint of the tube lens and are symmetric. However, for the opticalapparatus 1350, the “infinity space” between the objective lens 1340 andthe first tube lens 1381 has to be configured to meet the mechanicalconstraint. In some embodiments, the “infinity space” has to bemaximized. In some embodiments, the “infinity space” has to beminimized. In some embodiments, a conjugate point, which corresponds tothe front focal point of the first tube lens 1381, has to be located asfar away from the edge of the tube lens 1381 as possible, in order tohave mechanical space available. In some embodiments, another conjugatepoint, which corresponds to the back focal point of the first tube lens1381, has to be located as close to the edge of the tube lens 1381 aspossible, in order to minimize the distance from the tube lens to theStructured light modulator. Thus, the BFL of the tube lens 1381 has tobe designed or configured to be minimized. In some other embodiments,the BFL of the tube lens 1381 has to be designed or configured to bemaximized.

Similarly, in some embodiments, the “infinity space” between theobjective lens 1340 and the second tube lens 1382 has to be maximized.In some other embodiments, the “infinity space” between the objectivelens 1340 and the second tube lens 1382 has to be minimized. Forexample, if the second tube lens 1382 has an effective focal length(EFL) of 180 mm, in a conventional tube lens design, the conjugates,which are the front focal point and the back focal point, would be 180mm from the midpoint of the tube lens 1382, on both sides. In theoptical apparatus 1350, in order to maximize the “infinity space”between the objective lens 1340 and the second tube lens 1382, the BFLof the tube lens 1382 can be configured or designed to be minimized, asshort as possible. In some other embodiments, the BFL of the tube lens1382 can be configured or designed maximized, as long as possible.Therefore, the conjugates of a front focal point and a back focal pointof the tube lenses 381, 1382 of the optical apparatus 1350 are notequally spaced from the midpoint and not symmetric.

FIG. 7A is an optical schematic for a tube lens 7381 of the opticalapparatus with an EFL of 155 mm. There is no commercially available tubelens with an EFL shorter than 162 mm currently. It is difficult todesign the tube lens with a short EFL of 155 mm because the light beamspassing the tube lens are being bended at a large angle, thus creatinglarge aberrations. Special considerations have to be taken in order tominimize the “infinity” space between the tube lens and the objective. Afront focal point and a back focal point of the tube lens are notequally spaced from a midpoint of the tube lens and are not locatedsymmetric. The BFL of the tube length is minimized. For example, the BFLof the tube length is about 133 mm, 134 mm, 135 mm, or 136 mm in someembodiments.

For example, the tube lens with EFL 155 mm can comprise a first surfacehaving a convex shape and a positive radius of curvature of about 91 mm,a second surface having a convex shape and a positive radius ofcurvature of about 42 mm, a third surface having a concave shape and anegative radius of curvature of about −62 mm, and a fourth surfacehaving a concave shape and a negative radius of curvature of about −116mm. The tube lens can have a clear aperture with a diameter lager than44, 45, 46, 47, 48, 49, 50 mm. For example, the tube lens can have aclear aperture with a diameter of about 48 mm.

FIG. 7B is an optical schematic for a tube lens 7831′ of the opticalapparatus with an EFL of 162 mm. The tube lens can comprise a firstsurface having a convex shape and a positive radius of curvature ofabout 95 mm, a second surface having a convex shape and a positiveradius of curvature of about 54 mm, a third surface having a concaveshape and a negative radius of curvature of about −56 mm, and a fourthsurface having a concave shape and a negative radius of curvature ofabout −105 mm. The tube lens has a clear aperture with a diameter lagerthan 44, 45, 46, 47, 48, 49, 50 mm. For example, the tube lens can havea clear aperture with a diameter of about 48 mm. A front focal point anda back focal point of the tube lens are not equally spaced from amidpoint and are not located symmetric. The BFL of the tube length isminimized. For example, the BFL of the tube length is about 144 mm, 145mm, 146 mm, or 147 mm in some embodiments.

FIG. 7C is an optical schematic for a tube lens 7831″ of the opticalapparatus with an EFL of 180 mm. The tube lens can comprise a firstsurface having a convex shape and a positive radius of curvature ofabout 95 mm, a second surface having a convex shape and a positiveradius of curvature of about 64 mm, a third surface having a concaveshape and a negative radius of curvature of about −60 mm, and a fourthsurface having a concave shape and a negative radius of curvature ofabout −126 mm. The tube lens has a clear aperture with a diameter lagerthan 44, 45, 46, 47, 48, 49, 50 mm. For example, the tube lens can havea clear aperture with a diameter of about 48 mm. A front focal point anda back focal point of the tube lens are not equally spaced from amidpoint and are not located symmetric. The BFL of the tube length isminimized. For example, the BFL of the tube length is 161 mm, 162 mm,163 mm, 164 mm, or 165 mm in some embodiments.

FIG. 7D is an optical schematic for a tube lens 7381′″ of the opticalapparatus with an EFL of 200 mm. The tube lens can comprise a firstsurface having a convex shape and a positive radius of curvature ofabout 160 mm, a second surface having a concave shape and a negativeradius of curvature of about −62 mm, a third surface having a concaveshape and a negative radius of curvature of about −80 mm, and a fourthsurface having a concave shape and a negative radius of curvature ofabout −109 mm. The tube lens has a clear aperture with a diameter lagerthan 44, 45, 46, 47, 48, 49, 50 mm. For example, the tube lens can havea clear aperture with a diameter of about 48 mm. A front focal point anda back focal point of the tube lens are not equally spaced from amidpoint and are not located symmetric. The BFL of the tube length isminimized. For example, the BFL of the tube length is 189 mm, 190 mm,191 mm, or 192 mm in some embodiments. For example, the BFL of the tubelength can be 191.08 mm.

Table 1 summarizes examples of BFL of the tube lenses of the opticalapparatus. Table 2 shows an example of lens data of a tube lens with anEFL of 155 mm of the optical apparatus. Table 3 shows an example of lensdata of a tube lens with an EFL of 162 mm of the optical apparatus.Table 4 shows an example of lens data of a tube lens with an EFL of 180mm of the optical apparatus. Table 5 shows an example of lens data of atube lens with an EFL of 200 mm of the optical apparatus.

TABLE 1 Examples of BFL of the tube lenses of the optical apparatusImaging Lens EFL Wavelength Diameter BFL (mm) Range (mm) Materials (mm)180.0 420-740 nm 47.7 S-LAL59, CaF2, S-NSL5 163.50 162.0 400-650 nm 47.7S-BAL35, CaF2, S-BAL2 145.49 155.0 360-650 nm 47.7 S-BSL7, CaF2, PBL6Y134.51

TABLE 2 An example of a tube lens with an EFL of 155 mm of the opticalapparatus Clear Radius Thickness Diameter Surface (mm) (mm) Glass (mm)OBJ STANDARD Infinity Infinity 0 STO STANDARD Infinity 115.1011 26 2STANDARD 90.76744 20.0761 SBSL7 47.7 3 STANDARD 41.86237 14.85168 CAF247.7 4 STANDARD −61.45853 11.84032 PBL6Y 47.7 5 STANDARD −116.2671134.4121 38.68294 IMA STANDARD Infinity 18.89307

TABLE 3 An example of a tube lens with an EFL of 162 mm of the opticalapparatus Clear Radius Thickness Diameter Surf (mm) (mm) Glass (mm) OBJInfinity Infinity 0 STO Infinity 115.1011 26 2 95.34819 15.08445 S-BAL3547.7 3 53.71813 15.01997 CAF2 47.7 4 −56.38092 9.528684 S-BAL2 47.7 5−104.6289 145.3663 38.663 IMA Infinity 18.84638

TABLE 4 An example of a tube lens with an EFL of 180 mm of the opticalapparatus Clear Radius Thickness Diameter Surf (mm) (mm) Glass (mm) OBJInfinity Infinity 0 STO Infinity 141.0062 26 2 95.28401 6.844706 S-LAL5947.7 3 63.96965 25.00471 CAF2 47.7 4 −59.26094 4.952314 S-NSL5 47.7 5−126.1989 163.4191 37.46184 IMA Infinity 16.04591

TABLE 5 An example of a tube lens with an EFL of 200 mm of the opticalapparatus Clear Radius Thickness Diameter Surf (mm) (mm) Glass (mm) OBJInfinity Infinity 0 STO Infinity 159.9649 21 2 159.7133 25.02974 S-FPL5347.7 3 −62.2007 3.80616 S-TIM8 47.7 4 −78.99881 3.793759 S-LAH66 47.7 5−108.8432 191.0868 47.8 IMA Infinity 24.38727

FIG. 8A illustrates another embodiment of an optical configuration thatcan be used by the optical system 8000. A first light source 8332 (i.e.a laser) can emit light to a lens relay 8001. The light can pass throughthe lens relay to a first mirror 8003, which can reflect the light topass through a first dichroic beam splitter 8336. The first dichroicbeam splitter 8336 also receives light from a second light source 8334(i.e, a brightfield LED) and reflects that light along with the lightfrom the first light source to pass through a second dichroic beamsplitter 8338. The second dichroic beam splitter 8338 can also receivelight from a third light source 8335, which can first emit light to astructured light modulator 8330, which can reflect all or a portion ofthe light to the second dichroic beam splitter 8338. An intermediatelaser focal plane 8017 for the lens relay 8001 can be located betweenthe first dichroic beam splitter 8336 and the second dichroic beamsplitter 8338. The second dichroic beam splitter reflects light from thethird light source 8335 and passes through light from the first lightsource 8332 and the second light source 8334 to a first tube lens 8381.The combined light passes through the first tube lens 8381 to a firstfilter 8346 and then to a third dichroic beam splitter 8339, which canreflect the light to an objective lens 8340 that focuses the light ontoa sample plane 8320. The sample plane 8320 is illuminated, heated,and/or excited by the combined light, and can emit light in response toexcitation that can pass back through the objective lens 8340 and thenpass through the third dichroic beam splitter 8339, through a secondfilter 8347, through a second tube lens 8382, and to an imaging sensor(i.e., a camera).

FIG. 8B illustrates another embodiment of an optical configuration thatcan be used by the optical system 8000′ with a first light source 8332(i.e., a laser), a second light source 8334 (i.e., a brightfield LED),and a third light source 8335. The second light source 8334 can emitlight to a first mirror 8003 that can reflect the light to and through afirst dichroic beam splitter 8336. The first dichroic beam splitter 8336can also receive light from a third light source 8335, which can firstemit light to a structured light modulator 8330, which can reflect allor a portion of the light to the first dichroic beam splitter 8336. Thelight is reflected or transmitted through the first dichroic beamsplitter 8336 to a first filter 8346, and then to a second dichroic beamsplitter 8338 that reflects the light to an objective lens 8340. A firstlight source 8332 can emit light to and through a collimation lens 8019and to a third dichroic beam splitter 8339 that reflects the lightthrough a second filter, through the second dichroic beam splitter 8338,and to the objective lens 8340. The combined light from all the lightsources are focused by the objective lens 8340 onto the sample plane,which can emit light after excitation back through the objective lens8340, through the second dichroic beam splitter 8338, through the secondfilter 8347, through the third dichroic beam splitter 8339, through asecond tube lens 8382, and to an imaging sensor 8348 (i.e., a camera).

FIG. 8C illustrates another embodiment of an optical configuration thatcan be used by the optical system 8000″ with a first light source 8332(i.e., a laser), a second light source 8334 (i.e., a brightfield LED),and a third light source 8335. The second light source 8334 can emitlight to a first mirror 8003 that can reflect the light to and through afirst dichroic beam splitter 8336. The first dichroic beam splitter 8336can also receive light from a third light source 8335, which can firstemit light to a structured light modulator 8330, which can reflect allor a portion of the light to the first dichroic beam splitter 8336. Thelight is reflected or transmitted through the first dichroic beamsplitter 8336 through a first tube lines 8381 and through a seconddichroic beam splitter 8338. The second dichroic beam splitter 8338 canalso receive light from the first light source 8332, which can firstemit light through a collimation lens 8019 before being reflected fromthe second dichroic beam splitter 8338. Light reflected and transmittedthrough the second dichroic beam splitter 8338 is transmitted through afirst filter 8346 to a third dichroic beam splitter 8339 that reflectsthe light to an objective lens 8340 that focuses the light onto a sampleplane 8320. The sample can emit light from the excitation and alsoreflect light that passes back through the objective lens 8340, throughthe third dichroic beam splitter 8339, through a second filter 8347,through a second tube lens 8382, and to an imaging sensor 8348 (i.e., acamera).

FIG. 8D illustrates yet another embodiment of an optical configurationthat can be used by the optical system 8000′″ with a first light source8332 (i.e., a laser), a second light source 8334 (i.e., a brightfieldLED), and a third light source 8335. The second light source 8334 canemit light to a first mirror 8003 that can reflect the light to andthrough a first dichroic beam splitter 8336. The first dichroic beamsplitter 8336 can also receive light from a third light source 8335,which can first emit light to a structured light modulator 8330, whichcan reflect all or a portion of the light to the first dichroic beamsplitter 8336. The light is reflected or transmitted through the firstdichroic beam splitter 8336, through a first tube lines 8381, through afirst filter 8346, and to a second dichroic beam splitter 8338 thatreflects the light through a third dichroic beam splitter 8339 to anobjective lens 8340. The first light source 8332 can emit light througha collimation lens 8019 to the third dichroic beam splitter 8339 thatcan reflect the light to the objective lens 8340. The combined light canbe focused by the objective lens onto the sample plane 8320 toilluminate, heat, and/or excite the sample. Light can be reflected andemitted from the sample back through the objective lens 8340, throughthe third dichroic beam splitter 8339, through the second dichroic beamsplitter 8338, through a second tube lens 8382, and to an imaging sensor8348 (i.e., a camera).

FIGS. 9A and 9B illustrate the use of an angular imaging technique, alsocalled Fourier ptychographic microscopy (FPM), that can be incorporatedinto any of the embodiments described herein. The angular imagingtechnique can be used to increase image resolution without increasingthe power of the objective. For example, this allows a 10× objective toachieve 20× resolution. FPM works by taking a plurality of relativelylow resolution images from a plurality of different angles. A higherresolution image is generated computationally from the plurality ofimages using an iterative process that switches between the spatial andFourier domains.

In step 1, the FPM method starts by taking an initial low resolutionimage, assigning it as an initial high-resolution image, and applying aFourier transform to the image to create broad spectrum in the Fourierdomain.

In step 2, a small subregion of the spectrum is selected by applying alow pass filter and a Fourier transformation is then applied to generatea new low resolution target image in the spatial domain. The low passfilter shape is a circular pupil that corresponds to the coherenttransfer function of the objective lens. The position of the low passfilter is selected to correspond to the angle of illumination of theimage that is being processed.

In step 3, the target image's amplitude component is replaced with thesquare root of the low-resolution measurement obtained under the currentillumination angle, to form an updated low-resolution target image. AFourier transform is applied to the updated low-resolution target image,which is used to replace the corresponding subregion of the initialhigh-resolution Fourier space.

In step 4, steps 2 and 3 are repeated for other subregions, making surethat the subregions overlap with neighboring subregions to ensureconvergence, and the process is repeated for all images.

In step 5, steps 2-4 are repeated until a self-consistent solution isachieved in Fourier space. A Fourier transform is then applied to bringthe converged solution back to the spatial domain, which is the finalhigh-resolution image.

FIG. 9A illustrates a simplified portion of the optical train thatincludes the structured light modulator 9330, a tube lens 9381, anobjective lens 9340, and the sample plane 9320. In FIG. 9A, the lightbetween the tube lens 9381 and the objective lens 9340 is collimated,and objective lens 9340 then focuses the collimated light onto thesample plane 9320. FIG. 9B illustrates the addition of a slide lens 9001between the structured light modulator 9330 and the tube lens 9381 thatcan be used for FPM. The slide lens 9001 can be slidably inserted andremoved from the optical train. In some embodiments, the system can haveone or more different slide lenses 9001 that can be each slidablyinserted and removed. In some embodiments, the position of the slidelens can be adjusted to generate a different image from a differentangle. The insertion of the slide lens causes (i) the light travelingfrom the tube lens 9381 to the objective lens 9340 to come to a focalpoint between the tube lens 9381 and the objective lens 9340 (instead ofbeing collimated), and (ii) the light traveling from the objective lens9340 to the sample plane 9320 to be collimated rather than coming to afocal point. By selectively lighting up different sections of thestructured light modulator 9330, the light hitting the sample plane 9320will arrive at different angles. Images of the sample plane 9320illuminated with light arriving from several angles are then combined asdescribed above to produce a higher resolution image. The structuredlight modulator can be divided into at least 8 different sections (sothat at least 8 images with the light arriving at the sample plane atdifferent angles are generated) in order for higher resolution to beachieved. Dividing the structured light modulator into even moresections, such as 12, 16, 20, 24, etc. different sections to generatedifferent angles/images will produce still better resolutions.

The system can include a computing device with a processor and memorythat is programmed to perform the FPM computations described above.

Various embodiments of a method of manipulating one or moremicro-objects of a sample are disclosed herein. The method can comprisea step of loading the sample containing the one or more micro-objectsinto a microfluidic device having an enclosure. For example, themicrofluidic device can comprise a substrate having a surface and aplurality of dielectrophoresis (DEP) electrodes on the surface and aflow region and a plurality of sequestration pens, each sequestrationpen of the plurality fluidically connected to the flow region.

The method can comprise a step of applying a voltage potential acrossthe microfluidic device. The method can comprise a step of selectivelyactivating a DEP force adjacent to at least one micro-object locatedwithin the microfluidic device by using an optical apparatus.

The optical apparatus can be used to project structured light onto afirst position on the surface of the substrate of the microfluidicdevice, wherein the first position is located adjacent to a secondposition on the surface of the substrate, the second position locatedbeneath the at least one micro-object.

The optical apparatus can comprise a first light source, a structuredlight modulator, a first and a second tube lens, an objective lens, adichroic beam splitter and an image sensor. The structured lightmodulator is configured to receive unstructured light from the firstlight source and transmit structured light suitable for selectivelyactivating one or more of the plurality of DEP electrodes on the surfaceof the substrate of the microfluidic device. The first tube lens isconfigured to capture the structured light from the structured lightmodulator and transmit the structured light to an objective lens. Theobjective lens is configured to receive the structured light transmittedfrom the first tube lens and project the structured light within theenclosure of the microfluidic device, and wherein the objective lens isfurther configured to receive light reflected or emitted from within atleast a portion of the enclosure within a field of view of the objectivelens. The dichroic beam splitter can be located between the first tubelens and the objective lens, where the dichroic beam splitter isconfigured to transmit to the objective lens the structured lightreceived from the first tube lens and to reflect light received from theobjective lens to a second tube lens. The second tube lens is configuredto receive the reflected light from the dichromic beam splitter and totransmit the reflected light upon an image sensor. The image sensor isconfigured to receive the reflected light from the second tube lens andrecord an image of the at least a portion of the enclosure within thefield of view of the objective lens.

The method can comprise a step of shifting the location of the DEP forcegenerated adjacent to at least one micro-object by using the opticalapparatus to move the structured light from the first position on thesurface of the substrate of the light-actuated microfluidic device to athird position on the surface of the substrate.

In some embodiments, the method can further comprise a step of capturingthe image of the at least a portion of the enclosure of the microfluidicdevice with the image sensor. In some embodiments, the imaged portion ofthe enclosure of the microfluidic device comprises at least onesequestration pen and at least one micro-object.

In some embodiments, the optical apparatus comprises a second lightsource that produces unstructured light, and wherein the method furthercomprises using the optical apparatus to project the unstructured lightfrom the second light source into the enclosure of the microfluidicdevice, thereby providing bright field illumination within theenclosure.

In some embodiments, the optical apparatus comprises a laser lightsource, and wherein the method further comprises using the opticalapparatus to project laser light from the laser light source onto thesurface of the substrate of the enclosure of the microfluidic device.

In some embodiments, the optical apparatus further comprises a seconddichroic beam splitter positioned between the structured light modulatorand the first tube lens, and wherein structured light transmitted by thestructured light modulator is reflected into the first tube lens by thesecond dichroic beam splitter.

In some embodiments, the unstructured light produced by the second lightsource is transmitted through the second dichroic beam splitter to thefirst tube lens. In some embodiments, the laser light produced by thelaser light source is transmitter through the second dichroic beamsplitter to the first tube lens.

In some embodiments, the structured light projected onto the firstposition on the substrate surface comprises a plurality of illuminationspots. In some embodiments, the first position on the substrate surfaceis located in the flow region of the microfluidic device, and whereinthe third position on the substrate surface is located within one of thesequestration pens of the plurality of sequestration pens.

In some embodiments, the structured light projected onto the firstposition on the substrate surface comprises a shape like a line segmentor a caret symbol. In some embodiments, the structured light projectedonto the first position on the substrate surface has a shape like theoutline of a polygon.

In some embodiments, the method can further comprise a step ofselectively activating DEP forces adjacent to a plurality ofmicro-objects located within the microfluidic device by using theoptical apparatus to project structured light onto a plurality of firstpositions on the surface of the substrate of the microfluidic device,wherein each of the plurality of first positions is located adjacent toa corresponding second position on the surface of the substrate, thecorresponding second position located beneath a correspondingmicro-object of the plurality.

In some embodiments, the method can further comprise a step of shiftingthe location of the DEP forces generated adjacent to the plurality ofmicro-objects by using the optical apparatus to move the imagedstructured light from the plurality of first positions on the substratesurface to a plurality of corresponding third positions on the substratesurface.

In some embodiments, the method can further comprise a step of capturingan image of at least a portion of the enclosure comprises imaging onlyan interior area of the flow region and each sequestration pen locatedin the portion of the enclosure being imaged, thereby reducing overallnoise to achieve high image quality. In some embodiments, the method canfurther comprise a step of analyzing the image to provide feedback andadjustment of the first position.

Disclosed herein is a method of imaging one or more micro-objects of asample. The method can comprise loading the sample containing the one ormore micro-objects into a microfluidic apparatus having an enclosurecomprising a flow region.

The method can comprise capturing a plurality of images of at least aportion of the enclosure containing the one or more micro-objects usinga plurality of corresponding illumination patterns projected into the atleast a portion of the enclosure, wherein each illumination pattern ofthe plurality is produced using structured light and is different fromthe other illumination patterns of the plurality, and wherein theplurality of images is captured using an optical apparatus.

The optical apparatus can comprise a first light source, a structuredlight modulator, a first and a second tube lens, an objective lens, adichroic beam splitter, and an image sensor. The structured lightmodulator is configured to receive unstructured light from the firstlight source and transmit structured light corresponding to any of theplurality of illumination patterns. The first tube lens is configured tocapture the structured light from the structured light modulator andtransmit the structured light to an objective lens. The objective lensis configured to receive the structured light transmitted from the firsttube lens and project, and wherein the objective lens is furtherconfigured to receive light reflected or emitted from within the atleast a portion of the enclosure. The dichroic beam splitter is locatedbetween the first tube lens and the objective lens, the dichroic beamsplitter is configured to transmit to the objective lens the structuredlight received from the first tube lens and to reflect light receivedfrom the objective lens to a second tube lens. The second tube lens isconfigured to receive the reflected light from the dichromic beamsplitter and to transmit the reflected light upon the image sensor. Theimage sensor is configured to receive the reflected light from thesecond tube lens and record an image therefrom. The method can furthercomprise combining the plurality of images to generate a single image ofthe one or more micro-objects located in the portion of the enclosure,wherein the combining step comprises processing each of the plurality ofimages to remove out-of-focus background light.

In some embodiments, the microfluidic apparatus comprises a flow region,and wherein the one or more micro-objects are located in the flowregion. In some embodiments, the microfluidic apparatus comprises a flowregion and a plurality of sequestration pens, each sequestration pen ofthe plurality fluidically connected to the flow region, and wherein theone or more micro-objects are located in one or more of the plurality ofsequestration pens and/or the flow region.

In some embodiments, the plurality of corresponding illuminationpatterns projected into the at least a portion of the enclosure and thecorresponding image captured at the image sensor are simultaneously infocus. In some embodiments, the plurality of corresponding illuminationpatterns is configured to scan through the field of view within theenclosure.

Although particular embodiments of the disclosed invention have beenshown and described herein, it will be understood by those skilled inthe art that they are not intended to limit the present invention, andit will be obvious to those skilled in the art that various changes andmodifications may be made (e.g., the dimensions of various parts)without departing from the scope of the disclosed invention, which is tobe defined only by the following claims and their equivalents. Thespecification and drawings are, accordingly, to be regarded in anillustrative rather than restrictive sense.

Recitation of Embodiments of the Disclosure.

1. An optical apparatus for imaging micro-objects in an enclosure of amicrofluidic device, the optical apparatus including: a structured lightmodulator configured to receive unstructured light beams from a firstlight source and reflect or transmit structured light beams suitable forilluminating micro-objects located in enclosure of the microfluidicdevice;

-   first tube lens configured to capture and transmit the structured    light beams from the structured light modulator;-   an objective lens configured to capture and transmit image light    beams from a field of view including at least a portion of the    enclosure of the microfluidic device;-   a first dichroic beam splitter configured to receive and reflect or    transmit the structured light beams from the first tube lens, and    further configured to receive and transmit or reflect the image    light beams from the objective lens;-   a second tube lens configured to receive and transmit the image    light beams from the first dichroic beam splitter; and-   an image sensor configured to receive the image light beams from the    second tube lens, wherein the image sensor forms an image of the    field of view based upon the image light beams received from the    second tube lens.

2. The optical apparatus of embodiment 1, wherein the structured lightmodulator comprises an active area of at least 15 mm. In someembodiments, the structured light modulator may comprise an active areaof at least 15.5 mm, 16.0 mm, 16.5 mm, 17.0 mm, or greater.

3. The optical apparatus of embodiment 1 or 2, wherein the first tubelens has a clear aperture of at least 45 mm.

4. The optical apparatus of embodiment 3, wherein the first tube lenshas a clear aperture configured to capture substantially all light beamsfrom the structured light modulator (e.g., all or substantially allstructured light beams from the structured light modulator).

5. The optical apparatus of any one of embodiments 1 to 4, wherein thefirst tube lens has an effective focal length of about 162 mm (e.g., 162mm+/−0.8 mm) or shorter.

6. The optical apparatus of any one of embodiments 1 to 4, wherein thefirst tube lens has an effective focal length of about 155 mm (e.g.,155+/−0.8 mm).

7. The optical apparatus of any one of embodiments 1 to 5, wherein thefirst tube lens has a numerical aperture of about 0.071 to about 0.085.In some embodiments, the first tube lens may have a numerical apertureof about 0.074 to about 0.082, or about 0.076 to about 0.080.

8. The optical apparatus of any one of embodiments 1 to 7, wherein thesecond tube lens has an effective focal length of 180 mm+/−0.9 mm (orgreater).

9. The optical apparatus of any one of embodiments 1 to 7, wherein thesecond tube lens has an effective focal length of 200 mm+/−1 mm.

10. The optical apparatus of any one of embodiments 1 to 9, wherein thesecond tube lens has a numerical aperture of about 0.063 to about 0.077.In some embodiments, the second tube lens may have a numerical apertureof about 0.066 to about 0.074, or about 0.068 to about 0.072.

11. The optical apparatus of any one of embodiments 1 to 10, wherein theimage sensor comprises an active area of at least 16.5 mm. In someembodiments, the image sensor may comprise an active area of at least17.0 mm, 17.5 mm, 18.0 mm, 18.5 mm, 19.0 mm, or greater.

12. The optical apparatus of any one of embodiments 1 to 11, wherein theapparatus is characterized by an aperture stop at the back of theobjective lens, wherein the aperture stop is at least 25 mm. In someembodiments, the aperture stop is at least 26 mm, 27 mm, 28 mm, 29 mm,or greater, or 24 mm to 26 mm.

13. The optical apparatus of any one of embodiments 1 to 12, wherein thefirst dichroic beam splitter is configured to (i) reflect light beamsfrom the first tube lens to the objective lens, and (ii) transmit lightbeams from the objective lens to the second tube lens.

14. The optical apparatus of any one of embodiments 1 to 12, wherein thefirst dichroic beam splitter is configured to (i) transmit light beamsfrom the first tube lens to the objective lens, and (ii) reflect lightbeams from the objective lens to the second tube lens.

15. The optical apparatus of any one of embodiments 1 to 14, wherein theobjective lens is configured to minimize aberration in the image of thefield of view formed by the image sensor.

16. The optical apparatus of embodiment 16, wherein the second tube lensis configured to correct a residual aberration of the objective lens.

17. The optical apparatus of embodiment 15 or 16, further including acorrection lens configured to correct a residual aberration of theobjective lens.

18. The optical apparatus of any one of embodiments 1 to 17, wherein thestructured light modulator is disposed at a conjugate plane of the imagesensor.

19. The optical apparatus of any one of embodiments 1 to 18, wherein theapparatus is configured to perform confocal imaging.

20. The optical apparatus of any one of embodiments 1 to 17 furtherincluding a slide lens which is slideably positioned between thestructured light modulator and the first tube lens, wherein the slidelens is configured to support ptychographic microscopy.

21. The optical apparatus of any one of embodiments 1 to 20 furtherincluding a first light source.

22. The optical apparatus of embodiment 21, wherein the first lightsource has a power of at least 10 Watts.

23. The optical apparatus of embodiment 21 or 22, wherein the structuredlight beams reflected or transmitted by the structured light modulatorare suitable for selectively activating one or more of a plurality ofdielectrophoresis (DEP) electrodes on or comprised by a surface of asubstrate of the microfluidic device.

24. The optical apparatus of embodiment 21 or 22 further including asecond light source (e.g., an LED or laser).

25. The optical apparatus of embodiment 24, wherein the second lightsource is configured to provide unstructured bright field illumination.

26. The optical apparatus of embodiment 24 or 25, wherein the secondlight source comprises a laser.

27. The optical apparatus of any one of embodiments 1 to 26 furtherincluding a second dichroic beam splitter. (e.g., the second dichroicbeam splitter may be configured to reflect structured light beams fromthe structured light modulator to the first tube lens; optionally, thesecond dichroic beam splitter can also transmit unstructured light beamsfrom the second light source to the first tube lens)

28. The optical apparatus of any one of embodiments 24 to 27 furthercomprising a third light source.

29. The optical apparatus of embodiment 28, wherein the third lightsource comprises a laser, and optionally, wherein the laser of the thirdlight source is configured to heat an internal surface of themicrofluidic device and/or a liquid medium located within the enclosureof the microfluidic device (e.g., the laser may be configured to heat byan amount sufficient to generate a gas bubble within the enclosure ofthe microfluidic device).

30. The optical apparatus of any one of embodiments 1 to 29 furtherincluding a nest, wherein the nest is configured to hold themicrofluidic device.

31. The optical apparatus of embodiment 30, wherein the nest is furtherconfigured to provide at least one electrical connection to themicrofluidic device.

32. The optical apparatus of embodiment 30 or 31, wherein the nest isfurther configured to provide fluidic connections to the microfluidicdevice.

33. The optical apparatus of any one of embodiments 1 to 32, wherein themicrofluidic device includes a cover including glass, and wherein thecover has a thickness of about 600 microns or greater (e.g., the covermay have a thickness of about 600 microns to about 1000 microns, about625 microns to about 850 microns, or about 640 microns to about 700microns).

34. The optical apparatus of any one of embodiments 1 to 33 furtherincluding a control unit for providing instructions to the structuredlight modulator, wherein the instructions cause the structured lightmodulator to produce one or more illumination patterns.

35. The optical apparatus of embodiment 34, wherein the illuminationpatterns vary over time (e.g., a first pattern is replaced by a secondpattern, which is replaced by a third pattern, and so on, such that thepattern appears to move as a function of time).

36. A system for imaging micro-objects, the system including:

-   a microfluidic device including an enclosure, wherein the enclosure    comprises a substrate having a plurality of dielectrophoresis (DEP)    electrodes disposed on or comprised by a surface of the substrate;-   an optical apparatus configured for imaging of micro-objects in the    enclosure of the microfluidic device, the optical apparatus    including:-   a structured light modulator configured to receive unstructured    light from a first light source and reflect or transmit structured    light beams suitable for illuminating micro-objects located in the    enclosure of the microfluidic device;-   a first tube lens configured to capture and transmit the structured    light beams from the structured light modulator;-   an objective lens configured to capture and transmit image light    beams from a field of view including at least a portion of the    enclosure of the microfluidic device;-   a first dichroic beam splitter configured to receive and reflect or    transmit the structured light beams from the first tube lens, and    further configured to receive and transmit or reflect the image    light beams from the objective lens;-   a second tube lens configured to receive and transmit the image    light beams from the first dichroic beam splitter;-   an image sensor configured to receive the image light beams from the    second tube lens, wherein the image sensor forms an image of the    field of view based upon the image light beams received from the    second tube lens; and-   a nest for holding the microfluidic device in a position allowing    the microfluidic device to be imaged by the optical apparatus.

37. The system of embodiment 36, wherein the optical apparatus isconfigured according to any one of embodiments 2 to 29.

38. The system of embodiment 36 or 37, wherein the nest provides atleast one electrical connection to the microfluidic device.

39. The system of any one of embodiments 36 to 38, wherein the nextprovides fluidic connections to the microfluidic device.

40. The system of any one of embodiments 36 to 39 further including acontrol unit for providing instructions to the structured lightmodulator, wherein the instructions cause the structured light modulatorto produce one or more illumination patterns.

41. The system of embodiment 40, wherein the illumination patterns varyover time (e.g., a first pattern is replaced by a second pattern, whichis replaced by a third pattern, and so on, such that the pattern appearsto move as a function of time).

42. A method of manipulating one or more micro-objects of a sample, themethod including:

-   loading the sample containing the one or more micro-objects into a    microfluidic device having an enclosure including a substrate,    wherein the substrate comprises a plurality of light-actuated    dielectrophoresis (DEP) electrodes disposed on or comprised by a    surface of the substrate;-   applying a voltage potential across the microfluidic device;-   selectively activating a DEP force adjacent to at least one    micro-object located within the microfluidic device by using an    optical apparatus to project structured light onto a first position    on the surface of the substrate of the microfluidic device, wherein    the first position comprises one or more of the plurality of    light-actuated DEP electrodes and is located adjacent to a second    position on the surface of the substrate, the second position    located beneath the at least one micro-object, and wherein the    optical apparatus comprises: a first light source; a structured    light modulator configured to receive unstructured light beams from    the first light source and transmit structured light beams suitable    for selectively activating the one or more DEP electrodes at the    first position on the surface of the substrate of the microfluidic    device; a first tube lens configured to capture and transmit the    structured light beams from the structured light modulator; an    objective lens configured to capture the structured light beams    transmitted from the first tube lens and project the structured    light beams onto the first position on the surface of the substrate    of the microfluidic device, and wherein the objective lens is    further configured to capture and transmit image light beams    reflected or emitted from a field of view including at least a    portion of the enclosure of the microfluidic device, the field of    view encompassing the first and second positions on the surface of    the substrate; a first dichroic beam splitter configured to reflect    or transmit to the objective lens the structured light beams    received from the first tube lens, and further configured to    transmit or reflect image light beams received from the objective    lens; a second tube lens configured to receive and transmit the    image light beams from the first dichromic beam splitter; and an    image sensor configured to receive the image light beams from the    second tube lens, wherein the image sensor records an image of the    field of view based upon the image light beams received from the    second tube lens; and-   shifting the location of the DEP force generated adjacent to at    least one micro-object by using the optical apparatus to move the    projected structured light from the first position on the surface of    the substrate of the microfluidic device to a third position on the    surface of the substrate, wherein the third position also comprises    one or more of the plurality of light-actuated DEP electrodes.

43. The method of embodiment 42, wherein the third position isencompassed by the field of view.

44. The method of embodiment 42 or 43, wherein the third positionoverlaps with or encompasses the second position.

45. The method of any one of embodiments 42 to 44 further includingrecording an image of the field of view with the image sensor.

46. The method of any one of embodiments 42 to 45, wherein the enclosureof the microfluidic device comprises a flow region, at least onesequestration pen fluidically connected thereto.

47. The method of embodiment 46, wherein the field of view encompasses asequestration pen of the at least one sequestration pen and at least aportion of the flow region.

48. The method of any one of embodiments 42 to 47, wherein the opticalapparatus comprises a second light source that produces unstructuredlight, and wherein the method further comprises: using the opticalapparatus to project the unstructured light from the second light sourceinto the enclosure of the microfluidic device, thereby providing brightfield illumination within the enclosure.

49. The method of any one of embodiments 42 or 48, wherein the opticalapparatus comprises a laser light source, and wherein the method furthercomprises: using the optical apparatus to project laser light from thelaser light source onto a surface within the enclosure of themicrofluidic device (e.g., a fourth position on the surface of thesubstrate).

50. The method of any one of embodiments 42 to 49, wherein the opticalapparatus further comprises a second dichroic beam splitter positionedbetween the structured light modulator and the first tube lens, andwherein the structured light beams transmitted by the structured lightmodulator are reflected into the first tube lens by the second dichroicbeam splitter.

51. The method of embodiment 50, wherein the unstructured light producedby the second light source is transmitted through the second dichroicbeam splitter to the first tube lens.

52. The method of embodiment 50 or 51, wherein the laser light producedby the laser light source is transmitted through the second dichroicbeam splitter to the first tube lens.

53. The method of any one of embodiments 42 to 52, wherein thestructured light projected onto the first position on the substratesurface comprises a plurality of illumination spots.

54. The method of embodiment 46, wherein the first position on thesubstrate surface is located in the flow region of the microfluidicdevice, and wherein the third position on the substrate surface islocated within one of the sequestration pens of the plurality ofsequestration pens.

55. The method of any one of embodiments 42 to 54, wherein thestructured light projected onto the first position on the substratesurface comprises a shape like a line segment or a caret symbol.

56. The method of embodiment 55, wherein the structured light projectedonto the first position on the substrate surface has a shape like theoutline of a polygon. In some embodiments the shape may have an outlineof a quadrilateral polygon, such as a square, rectangle, rhombus, etc.,or a pentagon, or the like.

57. The method of any one of embodiments 42 to 56 further including:

-   selectively activating DEP forces adjacent to a plurality of    micro-objects located within the microfluidic device by using the    optical apparatus to project structured light onto a plurality of    first positions on the surface of the substrate of the microfluidic    device, wherein each of the plurality of first positions comprises    one or more of the plurality of light-actuated DEP electrodes and is    located adjacent to a corresponding second position on the surface    of the substrate, the corresponding second position located beneath    a corresponding micro-object of the plurality; and-   shifting the location of the DEP forces generated adjacent to the    plurality of micro-objects by using the optical apparatus to move    the projected structured light from the plurality of first positions    on the substrate surface to a plurality of corresponding third    positions on the substrate surface.

58. The method of embodiment 47, wherein recording an image of the fieldof view comprises imaging only an interior area of the flow region andeach sequestration pen located in the field of view (e.g., therebyreducing overall noise to achieve high image quality).

59. The method of embodiment 45 further including analyzing the recordedimage to provide feedback and adjustment of the first position.

60. A method of imaging one or more micro-objects of a sample, themethod including: loading the sample containing the one or moremicro-objects into an enclosure of a microfluidic device;

-   capturing a plurality of images of a field of view encompassing at    least a portion of the enclosure containing the one or more    micro-objects using a plurality of corresponding illumination    patterns projected into the field of view, wherein each illumination    pattern of the plurality is produced using structured light and is    different from the other illumination patterns of the plurality, and    wherein the plurality of images is captured using an optical    apparatus including: a first light source; a structured light    modulator configured to receive unstructured light beams from the    first light source and transmit structured light beams corresponding    to any of the plurality of illumination patterns; a first tube lens    configured to capture and transmit the structured light beams from    the structured light modulator; an objective lens configured to    capture the structured light beams transmitted from the first tube    lens and project the structured light beams into the at least a    portion of the enclosure of the microfluidic device encompassed by    the field of view, wherein the objective lens is further configured    to receive image light beams reflected or emitted from within the    field of view; a first dichroic beam splitter configured to reflect    or transmit to the objective lens the structured light beams    received from the first tube lens, and further configured to    transmit or reflect image light beams received from the objective    lens; a second tube lens configured to receive and transmit the    image light beams from the first dichromic beam splitter; and an    image sensor configured to receive the image light beams from the    second tube lens, wherein the image sensor records an image of the    field of view based upon the image light beams received from the    second tube lens; and-   combining the plurality of digital images to generate a confocal    image of the one or more micro-objects located in the field of view,    wherein the combining step comprises processing each of the    plurality of images to remove out-of-focus background light.

61. The method of embodiment 60, wherein the microfluidic apparatuscomprises a flow region, and wherein the one or more micro-objects arelocated in the flow region.

62. The method of embodiment 60, wherein the microfluidic apparatuscomprises a flow region and a plurality of sequestration pens, eachsequestration pen of the plurality fluidically connected to the flowregion, and wherein the one or more micro-objects are located in one ormore of the plurality of sequestration pens and/or the flow region.

63. The method of any one of embodiments 60 to 62, wherein the pluralityof corresponding illumination patterns projected into the field of viewand the corresponding images captured at the image sensor aresimultaneously in focus.

64. The method of any one of embodiments 60 to 63, wherein the pluralityof corresponding illumination patterns is configured to scan through thefield of view.

65. A tube lens of an optical apparatus for imaging micro-objects inmicrofluidic device, the tube lens including:

-   a first surface having a convex shape and a first radius of    curvature;-   a second surface having a second radius of curvature;-   a third surface having a concave shape and a third radius of    curvature;-   a fourth surface having a concave shape and a fourth radius of    curvature; and-   a clear aperture with a diameter of at least 45 mm; wherein the    first radius of curvature is positive, the third radius of curvature    is negative, and the fourth radius of curvature is negative, and    wherein a front focal point and a back focal point of the tube lens    are not equally spaced from a midpoint of the tube lens and/or are    not located symmetric.

66. The tube lens of embodiment 65, wherein a Back Focal Length (BFL) ofthe tube lens is minimized.

67. The tube lens of embodiment 65, wherein the tube lens has anEffective Focal Length (EFL) of about 155 mm (e.g., 155 mm+/−1 mm) and aBack Focal Length (BFL) of about 135 mm (e.g., 135 mm+/−1 mm).

68. The tube lens of embodiment 65, wherein the tube lens has anEffective Focal Length (EFL) of about 162 mm (e.g., 162 mm+/−1 mm) and aBack Focal Length (BFL) of about 146 mm (e.g., 146 mm+/−1 mm).

69. The tube lens of embodiment 65, wherein the tube lens has anEffective Focal Length (EFL) of about 180 mm (e.g., 180 mm+/−1 mm) and aBack Focal Length (BFL) of about 164 mm (e.g., 164 mm+/−1 mm).

70. The tube lens of embodiment 65, wherein the tube lens has anEffective Focal Length (EFL) of about 200 mm (e.g., 200 mm+/−1 mm) and aBack Focal Length (BFL) of about 191 mm (e.g., 191 mm+/−1 mm).

71. The tube lens of embodiment 65, wherein the tube lens has anEffective Focal Length (EFL) of about 155 mm (e.g., 155 mm+/−0.78 mm),wherein the first radius of curvature is about 91 mm (e.g., 91 mm+/−0.45mm), the second radius of curvature is about 42 mm (e.g., 42 mm+/−0.21mm), the third radius of curvature is about −62 mm (e.g., −62 mm+/−0.31mm), and the fourth radius of curvature is about −116 mm (e.g., −116mm+/−0.58 mm).

72. The tube lens of embodiment 65, wherein the tube lens has anEffective Focal Length (EFL) of about 162 mm (e.g., 162 mm+/−0.81 mm),wherein the first radius of curvature is about 95 mm (e.g., 95 mm+/−0.48mm), the second radius of curvature is about 54 mm (e.g., 54 mm+/−0.27mm), the third radius of curvature is about −56 mm (e.g., −56 mm+/−0.28mm), and the fourth radius of curvature is about −105 mm (e.g., −105mm+/−0.53 mm).

73. The tube lens of embodiment 65, wherein the tube lens has anEffective Focal Length (EFL) of about 180 mm (e.g., 180 mm+/−0.90 mm),wherein the first radius of curvature is about 95 mm (e.g., 95 mm+/−0.48mm), the second radius of curvature is about 64 mm (e.g., 64 mm+/−32mm), the third radius of curvature is about −60 mm (e.g., −60 mm+/−0.30mm), and the fourth radius of curvature is about −126 mm (e.g., −126mm+/−0.63 mm).

74. The tube lens of embodiment 65, wherein the tube lens has anEffective Focal Length (EFL) of about 200 mm (e.g., 200 mm+/−1.0 mm),wherein the first radius of curvature is about 160 mm (e.g., 160mm+/−0.80 mm), the second radius of curvature is about −62 mm (e.g., −62mm+/−0.31 mm), the third radius of curvature is about −80 mm (e.g., −80mm+/−0.40 mm), and the fourth radius of curvature is about −109 mm(e.g., −109 mm+/−0.55 mm).

75. A method of imaging one or more micro-objects of a sample, themethod including:

-   loading the sample containing the one or more micro-objects into an    enclosure of a microfluidic device;-   capturing a plurality of images of a field of view encompassing at    least a portion of the enclosure containing the one or more    micro-objects using a corresponding plurality of light illumination    angles projected into the field of view, wherein the plurality of    images is captured using an optical apparatus including: a first    light source; a structured light modulator configured to receive    unstructured light beams from the first light source and transmit    structured light beams corresponding to any of the plurality of    illumination patterns; a first tube lens configured to capture and    transmit the structured light beams from the structured light    modulator; an objective lens configured to capture the structured    light beams transmitted from the first tube lens and project the    structured light beams into the at least a portion of the enclosure    of the microfluidic device encompassed by the field of view, wherein    the objective lens is further configured to receive image light    beams reflected or emitted from within the field of view; a first    dichroic beam splitter configured to reflect or transmit to the    objective lens the structured light beams received from the first    tube lens, and further configured to transmit or reflect image light    beams received from the objective lens; a second tube lens    configured to receive and transmit the image light beams from the    first dichromic beam splitter; an image sensor configured to receive    the image light beams from the second tube lens; and a slide lens    positioned between the structured light modulator and the first tube    lens, wherein the slide lens is configured to support ptychographic    microscopy; and-   iteratively combining the plurality of captured images to generate a    composite image having higher resolution than any of the captured    images.

76. The method of embodiment 75, wherein the microfluidic apparatuscomprises a flow region, and wherein the one or more micro-objects arelocated in the flow region.

77. The method of embodiment 75, wherein the microfluidic apparatuscomprises a flow region and a plurality of sequestration pens, eachsequestration pen of the plurality fluidically connected to the flowregion, and wherein the one or more micro-objects are located in one ormore of the plurality of sequestration pens and/or the flow region.

78. The method of any one of embodiments 75 to 77, wherein the pluralityof captured images comprises at least eight images. In some embodiments,the plurality of captured images comprises at least 10, 12, 16, 20, 24,or more images.

79. The method of any one of embodiments 75 to 78, wherein the pluralityof light illumination angles is generated by structured lightoriginating from a corresponding plurality of different portions of thestructured light modulator.

80. The method of embodiment 79, wherein the different portions of thestructured light modulator are non-overlapping (or substantiallynon-overlapping).

What is claimed is:
 1. An optical apparatus for imaging micro-objects inan enclosure of a microfluidic device, the optical apparatus comprising:a structured light modulator configured to receive unstructured lightbeams from a first light source and reflect or transmit structured lightbeams suitable for illuminating micro-objects located in the enclosureof the microfluidic device; a first tube lens configured to capture andtransmit the structured light beams from the structured light modulator,comprising: a first surface having a convex shape and a first radius ofcurvature; a second surface having a second radius of curvature; a thirdsurface having a concave shape and a third radius of curvature; a fourthsurface having a concave shape and a fourth radius of curvature; and aclear aperture with a diameter of at least 45 mm, wherein the firstradius of curvature is positive, the third radius of curvature isnegative, and the fourth radius of curvature is negative, and wherein afront focal point and a back focal point of the tube lens are notequally spaced from a midpoint of the tube lens; an objective lensconfigured to capture and transmit image light beams from a field ofview comprising at least a portion of the enclosure of the microfluidicdevice; a first dichroic beam splitter configured to receive and reflector transmit the structured light beams from the first tube lens, andfurther configured to receive and transmit or reflect the image lightbeams from the objective lens; a second tube lens configured to receiveand transmit the image light beams from the first dichroic beamsplitter; and an image sensor configured to receive the image lightbeams from the second tube lens, wherein the image sensor forms an imageof the field of view based upon the image light beams received from thesecond tube lens.
 2. The optical apparatus of claim 1, wherein thestructured light modulator comprises an active area of at least 15 mm.3. The optical apparatus of claim 1, wherein the first tube lens has aneffective focal length of about 162 mm or shorter.
 4. The opticalapparatus of claim 1, wherein the first tube lens has an effective focallength of about 155 mm.
 5. The optical apparatus of claim 4, wherein thefirst tube lens has a numerical aperture of about 0.071 to about 0.085.6. The optical apparatus of claim 1, wherein the second tube lens has aneffective focal length of about 180 mm or longer.
 7. The opticalapparatus of claim 6, wherein the second tube lens has an effectivefocal length of about 200 mm.
 8. The optical apparatus of claim 1,wherein the second tube lens has a numerical aperture of about 0.063 toabout 0.077.
 9. The optical apparatus of claim 1, wherein the imagesensor comprises an active area of at least 18.0 mm.
 10. The opticalapparatus of claim 1, wherein the apparatus is characterized by anaperture stop at the back of the objective lens, wherein the aperturestop is at least 25 mm.
 11. The optical apparatus of claim 1, whereinthe objective lens is configured to minimize aberration in the image ofthe field of view formed by the image sensor.
 12. The optical apparatusof claim 11, wherein the second tube lens is configured to correct aresidual aberration of the objective lens.
 13. The optical apparatus ofclaim 11, further comprising a correction lens configured to correct aresidual aberration of the objective lens.
 14. The optical apparatus ofclaim 1, wherein the structured light modulator is disposed at aconjugate plane of the image sensor.
 15. The optical apparatus of claim1 further comprising a first light source.
 16. The optical apparatus ofclaim 15, wherein the first light source has a power of at least 10Watts.
 17. The optical apparatus of claim 15 further comprising a secondlight source.
 18. The optical apparatus of claim 17, wherein the secondlight source is configured to provide unstructured bright fieldillumination or wherein the second light source comprises a laser. 19.The optical apparatus of claim 1, further comprising a second dichroicbeam splitter.
 20. The optical apparatus of claim 17, further comprisinga third light source, wherein the third light source comprises a laser,and wherein the laser of the third light source is configured to heat aninternal surface of the microfluidic device and/or a liquid mediumlocated within the enclosure of the microfluidic device.
 21. The opticalapparatus of claim 1, further comprising a nest, wherein the nest isconfigured to hold the microfluidic device, provide at least oneelectrical connection to the microfluidic device, or provide fluidicconnections to the microfluidic device.
 22. The optical apparatus ofclaim 1, further comprising a control unit for providing instructions tothe structured light modulator, wherein the instructions cause thestructured light modulator to produce one or more illumination patterns.23. A method of manipulating one or more micro-objects of a sample, themethod comprising: loading the sample containing the one or moremicro-objects into a microfluidic device having an enclosure comprisinga substrate, wherein the substrate comprises a plurality oflight-actuated dielectrophoresis (DEP) electrodes disposed on orcomprised by a surface of the substrate; applying a voltage potentialacross the microfluidic device; selectively activating a DEP forceadjacent to at least one micro-object located within the microfluidicdevice by using an optical apparatus to project structured light onto afirst position on the surface of the substrate of the microfluidicdevice, wherein the first position comprises one or more of theplurality of light-actuated DEP electrodes and is located adjacent to asecond position on the surface of the substrate, the second positionlocated beneath the at least one micro-object, and wherein the opticalapparatus comprises: a first light source; a structured light modulatorconfigured to receive unstructured light beams from the first lightsource and transmit structured light beams suitable for selectivelyactivating the one or more DEP electrodes at the first position on thesurface of the substrate of the microfluidic device; a first tube lensconfigured to capture and transmit the structured light beams from thestructured light modulator; an objective lens configured to capture thestructured light beams transmitted from the first tube lens and projectthe structured light beams onto the first position on the surface of thesubstrate of the microfluidic device, and wherein the objective lens isfurther configured to capture and transmit image light beams reflectedor emitted from a field of view comprising at least a portion of theenclosure of the microfluidic device, the field of view encompassing thefirst and second positions on the surface of the substrate; a firstdichroic beam splitter configured to reflect or transmit to theobjective lens the structured light beams received from the first tubelens, and further configured to transmit or reflect image light beamsreceived from the objective lens; a second tube lens configured toreceive and transmit the image light beams from the first dichromic beamsplitter; and an image sensor configured to receive the image lightbeams from the second tube lens, wherein the image sensor records animage of the field of view based upon the image light beams receivedfrom the second tube lens; and shifting the location of the DEP forcegenerated adjacent to at least one micro-object by using the opticalapparatus to move the projected structured light from the first positionon the surface of the substrate of the microfluidic device to a thirdposition on the surface of the substrate, wherein the third positionalso comprises one or more of the plurality of light-actuated DEPelectrodes.
 24. The optical apparatus of claim 1, wherein a Back FocalLength (BFL) of the first tube lens is minimized.
 25. The opticalapparatus of claim 1, wherein the first tube lens has an Effective FocalLength (EFL) of about 155 mm (e.g., 155 mm+/−1 mm) and a Back FocalLength (BFL) of about 135 mm (e.g., 135 mm+/−1 mm).
 26. The opticalapparatus of claim 1, wherein the first tube lens has an Effective FocalLength (EFL) of about 162 mm (e.g., 162 mm+/−1 mm) and a Back FocalLength (BFL) of about 146 mm (e.g., 146 mm+/−1 mm).
 27. The opticalapparatus of claim 1, wherein the second tube lens has an EffectiveFocal Length (EFL) of about 180 mm (e.g., 180 mm+/−1 mm) and a BackFocal Length (BFL) of about 164 mm (e.g., 164 mm+/−1 mm).
 28. Theoptical apparatus of claim 1, wherein the second tube lens has anEffective Focal Length (EFL) of about 200 mm (e.g., 200 mm+/−1 mm) and aBack Focal Length (BFL) of about 191 mm (e.g., 191 mm+/−1 mm).
 29. Anoptical apparatus for imaging micro-objects in an enclosure of amicrofluidic device, the optical apparatus comprising: a structuredlight modulator configured to receive unstructured light beams from afirst light source and reflect or transmit structured light beamssuitable for illuminating micro-objects located in the enclosure of themicrofluidic device; a first tube lens configured to capture andtransmit the structured light beams from the structured light modulator;an objective lens configured to capture and transmit image light beamsfrom a field of view comprising at least a portion of the enclosure ofthe microfluidic device; a first dichroic beam splitter configured toreceive and reflect or transmit the structured light beams from thefirst tube lens, and further configured to receive and transmit orreflect the image light beams from the objective lens; a second tubelens configured to receive and transmit the image light beams from thefirst dichroic beam splitter, wherein the second tube lens comprises: afirst surface having a convex shape and a first radius of curvature; asecond surface having a second radius of curvature; a third surfacehaving a concave shape and a third radius of curvature; a fourth surfacehaving a concave shape and a fourth radius of curvature; and a clearaperture with a diameter of at least 45 mm; wherein the first radius ofcurvature is positive, the third radius of curvature is negative, andthe fourth radius of curvature is negative, and wherein a front focalpoint and a back focal point of the tube lens are not equally spacedfrom a midpoint of the tube lens; and an image sensor configured toreceive the image light beams from the second tube lens, wherein theimage sensor forms an image of the field of view based upon the imagelight beams received from the second tube lens.